ELECTRONIC SCIENCE-PAGE 2
ELECTRONIC SCIENCE MCQs
1. Match the following lists:
List – I List – II
a. Early affect i. IC Fabrication
b. Masking ii. JFET
c. Enhancement iii. MOSFET
d. Pinch off iv. Transistor
The correct match is
a b c d
(A) i ii iv iii
(B) i iii ii iv
(C) iv iii i ii
(D) iv i iii ii
Ans: D
2. Match the following lists:
List – I List – II
a. Zeroes & Poles i. Linear elements
b. Ramp ii. ABCD
c. Super position iii. 1/S2
d. Transmission parameters iv. Stability
The correct match is
a b c d
(A) iv iii i ii
(B) iii i ii iv
(C) i ii iv iii
(D) ii iv ii i
Ans: A
3. Match the following lists:
List – I List – II
a. Virtual ground i. Time constant
b. L/R ii. Q-factor
c. WL/R iii. Op-Amp
d. Intrinsic standoff ratio iv. UJT
The correct match is
a b c d
(A) ii i iii iv
(B) iii iv i ii
(C) iii i ii iv
(D) iv i ii iii
Ans: C
4. Match the following lists:
List – I List – II
a. IC 7410 i. Hex Inverter
b. IC 7404 ii. Quad 2 input ORgate
c. IC 7432 iii. JK master slave flip flop
d. IC 7472 iv. Triple 3-input NAND gate
The correct match is
a b c d
(A) iv ii i iii
(B) iv i ii iii
(C) i ii iii iv
(D) ii iv i iii
Ans: B
5. Match the following lists:
List – I List – II
a. IC 8051 i. Stack
b. Nonmaskable ii. Implied addressing mode
c. PUSH iii. TRAP
d. CMA iv. Microcontroller
The correct match is
a b c d
(A) iv iii i ii
(B) iv ii i iii
(C) iii i ii iv
(D) ii iii iv i
Ans: A
6. Match the following lists:
List – I List – II
a. Envelope detector i. TV transmission
b. Foster Seley discriminator ii. Frequency modulation
c. Varacter diode iii. FM detection
d. Vestigial side band iv. AM demodulation
The correct match is given by
a b c d
(A) iv iii ii i
(B) i ii iii iv
(C) ii iv iii i
(D) i ii iv iii
Ans: A
7. Match the following lists:
List – I List - II
(a) Alpha of Transistor (i)> 1
(b) Beta of Transistor (ii) ∞
(c) CMRR (Common Mode Rejection Ratio) (iii)< 1
(d) PSRR (Power Supply Rejection Ratio) (iv) 0
The correct match is:
(a) (b) (c) (d)
(A) (iii) (i) (ii) (iv)
(B) (iv) (i) (ii) (iii)
(C) (i) (ii) (iii) (iv)
(D) (ii) (i) (iii) (iv)
Ans: A
8. Match the following lists:
List – I List - II
(a) Magnetron (i) Detector
(b) Pin diode (ii) Bunching
(c) Klystron (iii) Low Power Oscillator
(d) Gunn diode (iv) π-mode
The correct match is:
(a) (b) (c) (d)
(A) (ii) (iii) (iv) (i)
(B) (i) (ii) (iii) (iv)
(C) (iii) (i) (ii) (iv)
(D) (iv) (i) (ii) (iii)
Ans: D
9. Match the following lists:
List – I List - II
(a) Companding (i) Improving image rejection
(b) Squelch (ii) Variation of step rise in quantisation
(c) Preemphasis (iii) Muting the receiver
(d) Double conversion (iv) Boosting of higher modulating frequencies at the transmitter
Codes:
(a) (b) (c) (d)
(A) (ii) (iii) (iv) (i)
(B) (ii) (i) (iv) (iii)
(C) (i) (ii) (iii) (iv)
(D) (i) (ii) (iv) (iii)
Ans: A
10. Match the following lists:
List – I List - II
(a) 74150 (i) Quad 2: 1 Multiplexer
(b) 74152 (ii) Dual 4: 1 Multiplexer
(c) 74153 (iii) 8: 1 Multiplexer
(d) 74157 (iv) 16: 1 Multiplexer
Codes:
(a) (b) (c) (d)
(A) (i) (ii) (iii) (iv)
(B) (iv) (iii) (ii) (i)
(C) (iv) (ii) (iii) (i)
(D) (ii) (i) (iv) (iii)
Ans: B
11. Match the following lists:
List – I List - II
(Characteristic of the device) (Device)
(a) Voltage controlled device (i) BJT
(b) Current controlled device (ii) UJT
(c) Conductivity modulated device (iii) FET
(d) Negative conductance device (iv) IMPATT
Codes:
(a) (b) (c) (d)
(A) (ii) (iii) (i) (iv)
(B) (ii) (iii) (iv) (i)
(C) (iii) (i) (iv) (ii)
(D) (iii) (i) (ii) (iv)
Ans: C
12. Match the following lists:
List – I List - II
(a) Optical fiber communication (i) FDM
(b) Mobile communication (ii) TDM
(c) Digital communication (iii) CDMA
(d) Analog communication (iv) Wavelength- Division Multiplexing (WDM)
Codes:
(a) (b) (c) (d)
(A) (i) (iii) (ii) (iv)
(B) (iv) (iii) (ii) (i)
(C) (ii) (iv) (i) (iii)
(D) (iii) (i) (ii) (iii)
Ans: B
13. Match the following lists:
List – I List - II
(a) Bode’s-Plot representation (i) not a frequency domain technique.
(b) Nyquist Diagram (ii) low frequency and high frequency characteristics of the transfer function can be determined
(c) Nichols Charts (iii) decides the Stability criteria
(d) Root-locus Method (iv) also known as Polar plots
Codes:
(a) (b) (c) (d)
(A) (iv) (iii) (i) (ii)
(B) (iv) (iii) (ii) (i)
(C) (iii) (iv) (i) (ii)
(D) (ii) (iii) (iv) (i)
Ans: D
14. Match the following
List – I List – II
a. SCR i. dc drive control
b. Triac ii. Induction motor control
c. Chopper iii. Unidirectional
d. Cycloconverter iv. Bidirectional
Codes:
a b c d
(A) iv iii i ii
(B) i ii iii iv
(C) iii iv i ii
(D) i iv ii iii
Ans: C
15. Match the following
List – I List – II
a. Varistor i. nonlinear resistance
b. Varactor diode ii. Nonlinear reactance
c. Gunn diode iii. Negative resistance
d. PIN diode iv. Controllable impedance type
Codes:
a b c d
(A) i ii iii iv
(B) ii iii iv i
(C) iii iv i ii
(D) iv i ii iii
Ans: A
16. Match the following
List – I List – II
a. Klystron i. Cross-field device
b. Reflex Klystron ii. Bunching
c. Magnetron iii. Velocity modulation
d. Gunn diode iv. Negative resistance
Codes:
a b c d
(A) ii iii i iv
(B) i ii iii iv
(C) iv i ii iii
(D) i ii iv iii
Ans: A
17. Match the following
List – I List – II
a. LED i. Stimulated emission
b. LASER ii. Spontaneous emission
c. Solar Cell iii. Power generator
d. Photo diode iv. Detector
Codes:
a b c d
(A) i ii iii iv
(B) ii i iii iv
(C) iii iv i ii
(D) iv i ii iii
Ans: B
18. Match the following:
List – I List – II
a. LED i. Heavily doped
b. APD ii. Coherent radiation
c. Tunnel diode iii. Spontaneous emission
d. Laser iv. Current gain
The correct sequence is given by
a b c d
(A) ii i iii iv
(B) iv iii ii i
(C) iii iv i ii
(D) iii ii i iv
Ans: C
19. Match the following:
List – I List – II
a. Cassegrain antenna i. Large B.W.
b. Yagi antenna ii. Direction finding
c. Parabolic reflector antenna iii. Radar
d. Loop antenna iv. Directional transmission
a b c d
(A) i iv ii iii
(B) iii i iv ii
(C) ii iv iii i
(D) iii ii iv i
Ans: B
20. Match the following lists:
List – I List – II
(Band gap in eV) (Materials)
a. 0.67 i. Ga As
b. 1.1 ii. Cadmium sulphate
c. 1.4 iii. Si
d. 2.4 iv. Ge
The correct matching order is
a b c d
(A) iv iii i ii
(B) iii ii i iv
(C) iv i iii ii
(D) ii iii i iv
Ans: A
21. Match the following:
List – I List – II
a. Voltage series feedback connection i. increases input impedance
b. Voltage shunts feedback connection ii. Decreases the input impedance
c. Current series feedback connection iii. Increases the output impedance
d. Voltage series feedback connection iv. Decreases the output impedance
The correct matching order is
a b c d
(A) iv ii iii i
(B) iv ii i iii
(C) i iii iv ii
(D) i ii iii iv
Ans: D
22. Match the following lists:
List – I List – II
a. Electromyogram i. Tracing brain waves
b. Electrocardiogram ii. Tracing of muscular waves
c. Electroencephalogram iii. Measurement of air in lungs
d. Spirometer iv. A record of electrical activity of heart
a b c d
(A) i ii iii iv
(B) i iv iii ii
(C) i iv ii iii
(D) iv iii i ii
Ans: C
23. Match the following:
List – I List – II
a. Removes ac ripple i. Zener diode
b. Supplies ac input voltage ii. Filter capacitor
c. Constant dc output voltage iii. No output voltage
d. Filter choke inductor iv. Power transformer
a b c d
(A) ii iv i iii
(B) i iv iii ii
(C) iv i ii iii
(D) ii iii i iv
Ans: A
24. Match the following lists:
List – I List – II
a. Maxwells bridge i. Measurement of unknown inductance
b. Hay’s bridge ii. Measurement of high Q of coils
c. Schering’s bridge iii. Precision measurement of capacitance
d. Weins bridge iv. To measure frequency
a b c d
(A) i ii iii iv
(B) iv iii ii i
(C) iv ii iii i
(D) i iii ii iv
Ans: A
25. Match the following lists:
List – I List – II
a. Gamma rays i. 400-700 nm
b. Visible light ii. 1-10 cm
c. Radiowaves iii. 3 × 10+3 m
d. Microwaves iv. 4 × 10–11 m
a b c d
(A) i ii iii iv
(B) iv iii ii i
(C) iv i iii ii
(D) ii iii iv i
Ans: C
26. Match the List – I and List – II:
List – I List – II
(Type of counters) (No. of flip flops required)
a. Mod-6 i. 3
b. Mod-11 ii. 4
c. Mod-31 iii. 5
a b c
(A) iii ii i
(B) i ii iii
(C) ii iii i
(D) iii i ii
Ans: B
27. Match the following lists:
List – I List – II
(Units) (Quantity)
a. ps/nm/km i. Attenuation
b. dB/km ii. Magnetic field
c. cm2/v-s iii. Dispersion
d. Tesla iv. Mobility
a b c d
(A) iv i ii iii
(B) iii i ii iv
(C) iii i iv ii
(D) i iv iii ii
Ans: C
28. Match the following lists:
List – I List – II
a. DAA i. Program control instruction
b. LXI ii. Data movement instruction
c. RST iii. Interrupt instruction
d. JMP iv. Arithmetic instruction
Codes:
a b c d
(A) i ii iii iv
(B) iv ii iii i
(C) iii iv i ii
(D) ii i iii iv
Ans: B
29. Match the following lists:
List – I List – II
a. 8031 i. Multiplexer
b. 7490 ii. Demultiplexer
c. 74155 iii. Microcontroller
d. 74151 iv. Decade counter
Codes:
a b c d
(A) iii iv ii i
(B) i ii iii iv
(C) ii iii iv i
(D) iii i ii iv
Ans: A
30. Match the following lists:
List – I List – II
a. Bourdon tube i. Distance
b. Strain gauge ii. Temperature
c. Thermistor iii. Pressure
d. LVDT iv. Stress
Codes:
a b c d
(A) i ii iii iv
(B) iii iv ii i
(C) ii iii iv i
(D) i iii ii iv
Ans: B
31. Match the following lists:
List – I List – II
(Types of ADC) (Characteristics)
a. Parallel comparator (i.e. flash) type i. integrating type
b. Successive approximation ii. Fastest converter
c. Dual slope iii. Conversion time is independent of the amplitude of the analogue signal
d. Counter type iv. Uses DAC in feedback path
Codes:
a b c d
(A) ii iii i iv
(B) i ii iv iii
(C) iv iii ii i
(D) iv ii iii i
Ans: A
32. Match the following lists:
List – I List – II
a. Flip-Flop can be used as latch i. D Flip-flop
b. Flip-Flop can be used as delayed ii. Master- Slave
c. Flip-Flop does not have race problem iii. JK
d. Flip-flop can be used as shift registers iv. R-S
Codes:
a b c d
(A) iv i ii iii
(B) ii iv i iii
(C) i iii ii iv
(D) iii i iv ii
Ans: A
33. The following are features of a micro controller 8051:
(i) 4 k bytes of ROM or EPROM
(ii) 128 k bytes of data memory
(iii) Four programmable I/O ports
(iv) Three 16 bit timer/event counters.
(A) (i), (ii) and (iii)
(B) (i), (ii) and (iv)
(C) (i), (iii) and (iv)
(D) (ii), (iii) and (iv)
Ans: A
34. Identify the peripheral devices for their applications.
(a) 8155 (i) Serial Communication
(b) 8279 (ii) Timers and Counters
(c) 8253 (iii) Keyboard and display interface
(d) 8251 (iv) Additional input/output lines to processor
Codes:
(a) (b) (c) (d)
(A) (ii) (iii) (iv) (i)
(B) (iii) (iv) (i) (ii)
(C) (iv) (i) (ii) (iii)
(D) (iv) (iii) (ii) (i)
Ans: D
35. Match the following lists:
List – I List – II
a Stability of Control System (i). Oscillation in which the amplitude decreases with time.
b Unstability of Control System (ii). All roots of characteristic equation have negative real part.
c Frequency response (iii). Steady state response
d Damped Oscillation (iv) Any root of characteristic equation has a positive real part
Codes:
a b c d
(A) 4 2 3 1
(B) 2 4 3 1
(C) 2 4 1 3
(D) 4 2 1 3
Ans: B
36. Match the following lists:
List – I List – II
a. Slip i. Relaxation oscillator
b. SCR ii. Class-E chopper
c. UJT iii. Two-transistor model
d. dc drives iv. Induction motors
The correct match is
a b c d
(A) i ii iii iv
(B) iii iv i ii
(C) ii iii i iv
(D) iv iii i ii
Ans: D
37. Match the following lists:
List – I List – II
a. Intermodal dispersion i. Lasers
b. Chirp ii. SMF (Single Mode Fiber)
c. Intramodal dispersion iii. III-V group
d. Direct band gap semiconductors iv. MMF (Multimode Fiber)
The correct match is
a b c d
(A) iv i ii iii
(B) iii iv i ii
(C) ii i iii iv
(D) i ii iii iv
Ans: A
38. Match the following lists:
List – I List – II
a. LVDT i. Speed
b. Techogenerators ii. Resistance
c. Wheatstone Bridge iii. Displacement
d. Bourdon tube iv. Pressure
The correct match is given by
a b c d
(A) i ii iii iv
(B) iii i ii iv
(C) i iii ii iv
(D) iii ii i iv
Ans: B
List – I List – II
a. Early affect i. IC Fabrication
b. Masking ii. JFET
c. Enhancement iii. MOSFET
d. Pinch off iv. Transistor
The correct match is
a b c d
(A) i ii iv iii
(B) i iii ii iv
(C) iv iii i ii
(D) iv i iii ii
Ans: D
2. Match the following lists:
List – I List – II
a. Zeroes & Poles i. Linear elements
b. Ramp ii. ABCD
c. Super position iii. 1/S2
d. Transmission parameters iv. Stability
The correct match is
a b c d
(A) iv iii i ii
(B) iii i ii iv
(C) i ii iv iii
(D) ii iv ii i
Ans: A
3. Match the following lists:
List – I List – II
a. Virtual ground i. Time constant
b. L/R ii. Q-factor
c. WL/R iii. Op-Amp
d. Intrinsic standoff ratio iv. UJT
The correct match is
a b c d
(A) ii i iii iv
(B) iii iv i ii
(C) iii i ii iv
(D) iv i ii iii
Ans: C
4. Match the following lists:
List – I List – II
a. IC 7410 i. Hex Inverter
b. IC 7404 ii. Quad 2 input ORgate
c. IC 7432 iii. JK master slave flip flop
d. IC 7472 iv. Triple 3-input NAND gate
The correct match is
a b c d
(A) iv ii i iii
(B) iv i ii iii
(C) i ii iii iv
(D) ii iv i iii
Ans: B
5. Match the following lists:
List – I List – II
a. IC 8051 i. Stack
b. Nonmaskable ii. Implied addressing mode
c. PUSH iii. TRAP
d. CMA iv. Microcontroller
The correct match is
a b c d
(A) iv iii i ii
(B) iv ii i iii
(C) iii i ii iv
(D) ii iii iv i
Ans: A
6. Match the following lists:
List – I List – II
a. Envelope detector i. TV transmission
b. Foster Seley discriminator ii. Frequency modulation
c. Varacter diode iii. FM detection
d. Vestigial side band iv. AM demodulation
The correct match is given by
a b c d
(A) iv iii ii i
(B) i ii iii iv
(C) ii iv iii i
(D) i ii iv iii
Ans: A
7. Match the following lists:
List – I List - II
(a) Alpha of Transistor (i)> 1
(b) Beta of Transistor (ii) ∞
(c) CMRR (Common Mode Rejection Ratio) (iii)< 1
(d) PSRR (Power Supply Rejection Ratio) (iv) 0
The correct match is:
(a) (b) (c) (d)
(A) (iii) (i) (ii) (iv)
(B) (iv) (i) (ii) (iii)
(C) (i) (ii) (iii) (iv)
(D) (ii) (i) (iii) (iv)
Ans: A
8. Match the following lists:
List – I List - II
(a) Magnetron (i) Detector
(b) Pin diode (ii) Bunching
(c) Klystron (iii) Low Power Oscillator
(d) Gunn diode (iv) π-mode
The correct match is:
(a) (b) (c) (d)
(A) (ii) (iii) (iv) (i)
(B) (i) (ii) (iii) (iv)
(C) (iii) (i) (ii) (iv)
(D) (iv) (i) (ii) (iii)
Ans: D
9. Match the following lists:
List – I List - II
(a) Companding (i) Improving image rejection
(b) Squelch (ii) Variation of step rise in quantisation
(c) Preemphasis (iii) Muting the receiver
(d) Double conversion (iv) Boosting of higher modulating frequencies at the transmitter
Codes:
(a) (b) (c) (d)
(A) (ii) (iii) (iv) (i)
(B) (ii) (i) (iv) (iii)
(C) (i) (ii) (iii) (iv)
(D) (i) (ii) (iv) (iii)
Ans: A
10. Match the following lists:
List – I List - II
(a) 74150 (i) Quad 2: 1 Multiplexer
(b) 74152 (ii) Dual 4: 1 Multiplexer
(c) 74153 (iii) 8: 1 Multiplexer
(d) 74157 (iv) 16: 1 Multiplexer
Codes:
(a) (b) (c) (d)
(A) (i) (ii) (iii) (iv)
(B) (iv) (iii) (ii) (i)
(C) (iv) (ii) (iii) (i)
(D) (ii) (i) (iv) (iii)
Ans: B
11. Match the following lists:
List – I List - II
(Characteristic of the device) (Device)
(a) Voltage controlled device (i) BJT
(b) Current controlled device (ii) UJT
(c) Conductivity modulated device (iii) FET
(d) Negative conductance device (iv) IMPATT
Codes:
(a) (b) (c) (d)
(A) (ii) (iii) (i) (iv)
(B) (ii) (iii) (iv) (i)
(C) (iii) (i) (iv) (ii)
(D) (iii) (i) (ii) (iv)
Ans: C
12. Match the following lists:
List – I List - II
(a) Optical fiber communication (i) FDM
(b) Mobile communication (ii) TDM
(c) Digital communication (iii) CDMA
(d) Analog communication (iv) Wavelength- Division Multiplexing (WDM)
Codes:
(a) (b) (c) (d)
(A) (i) (iii) (ii) (iv)
(B) (iv) (iii) (ii) (i)
(C) (ii) (iv) (i) (iii)
(D) (iii) (i) (ii) (iii)
Ans: B
13. Match the following lists:
List – I List - II
(a) Bode’s-Plot representation (i) not a frequency domain technique.
(b) Nyquist Diagram (ii) low frequency and high frequency characteristics of the transfer function can be determined
(c) Nichols Charts (iii) decides the Stability criteria
(d) Root-locus Method (iv) also known as Polar plots
Codes:
(a) (b) (c) (d)
(A) (iv) (iii) (i) (ii)
(B) (iv) (iii) (ii) (i)
(C) (iii) (iv) (i) (ii)
(D) (ii) (iii) (iv) (i)
Ans: D
14. Match the following
List – I List – II
a. SCR i. dc drive control
b. Triac ii. Induction motor control
c. Chopper iii. Unidirectional
d. Cycloconverter iv. Bidirectional
Codes:
a b c d
(A) iv iii i ii
(B) i ii iii iv
(C) iii iv i ii
(D) i iv ii iii
Ans: C
15. Match the following
List – I List – II
a. Varistor i. nonlinear resistance
b. Varactor diode ii. Nonlinear reactance
c. Gunn diode iii. Negative resistance
d. PIN diode iv. Controllable impedance type
Codes:
a b c d
(A) i ii iii iv
(B) ii iii iv i
(C) iii iv i ii
(D) iv i ii iii
Ans: A
16. Match the following
List – I List – II
a. Klystron i. Cross-field device
b. Reflex Klystron ii. Bunching
c. Magnetron iii. Velocity modulation
d. Gunn diode iv. Negative resistance
Codes:
a b c d
(A) ii iii i iv
(B) i ii iii iv
(C) iv i ii iii
(D) i ii iv iii
Ans: A
17. Match the following
List – I List – II
a. LED i. Stimulated emission
b. LASER ii. Spontaneous emission
c. Solar Cell iii. Power generator
d. Photo diode iv. Detector
Codes:
a b c d
(A) i ii iii iv
(B) ii i iii iv
(C) iii iv i ii
(D) iv i ii iii
Ans: B
18. Match the following:
List – I List – II
a. LED i. Heavily doped
b. APD ii. Coherent radiation
c. Tunnel diode iii. Spontaneous emission
d. Laser iv. Current gain
The correct sequence is given by
a b c d
(A) ii i iii iv
(B) iv iii ii i
(C) iii iv i ii
(D) iii ii i iv
Ans: C
19. Match the following:
List – I List – II
a. Cassegrain antenna i. Large B.W.
b. Yagi antenna ii. Direction finding
c. Parabolic reflector antenna iii. Radar
d. Loop antenna iv. Directional transmission
a b c d
(A) i iv ii iii
(B) iii i iv ii
(C) ii iv iii i
(D) iii ii iv i
Ans: B
20. Match the following lists:
List – I List – II
(Band gap in eV) (Materials)
a. 0.67 i. Ga As
b. 1.1 ii. Cadmium sulphate
c. 1.4 iii. Si
d. 2.4 iv. Ge
The correct matching order is
a b c d
(A) iv iii i ii
(B) iii ii i iv
(C) iv i iii ii
(D) ii iii i iv
Ans: A
21. Match the following:
List – I List – II
a. Voltage series feedback connection i. increases input impedance
b. Voltage shunts feedback connection ii. Decreases the input impedance
c. Current series feedback connection iii. Increases the output impedance
d. Voltage series feedback connection iv. Decreases the output impedance
The correct matching order is
a b c d
(A) iv ii iii i
(B) iv ii i iii
(C) i iii iv ii
(D) i ii iii iv
Ans: D
22. Match the following lists:
List – I List – II
a. Electromyogram i. Tracing brain waves
b. Electrocardiogram ii. Tracing of muscular waves
c. Electroencephalogram iii. Measurement of air in lungs
d. Spirometer iv. A record of electrical activity of heart
a b c d
(A) i ii iii iv
(B) i iv iii ii
(C) i iv ii iii
(D) iv iii i ii
Ans: C
23. Match the following:
List – I List – II
a. Removes ac ripple i. Zener diode
b. Supplies ac input voltage ii. Filter capacitor
c. Constant dc output voltage iii. No output voltage
d. Filter choke inductor iv. Power transformer
a b c d
(A) ii iv i iii
(B) i iv iii ii
(C) iv i ii iii
(D) ii iii i iv
Ans: A
24. Match the following lists:
List – I List – II
a. Maxwells bridge i. Measurement of unknown inductance
b. Hay’s bridge ii. Measurement of high Q of coils
c. Schering’s bridge iii. Precision measurement of capacitance
d. Weins bridge iv. To measure frequency
a b c d
(A) i ii iii iv
(B) iv iii ii i
(C) iv ii iii i
(D) i iii ii iv
Ans: A
25. Match the following lists:
List – I List – II
a. Gamma rays i. 400-700 nm
b. Visible light ii. 1-10 cm
c. Radiowaves iii. 3 × 10+3 m
d. Microwaves iv. 4 × 10–11 m
a b c d
(A) i ii iii iv
(B) iv iii ii i
(C) iv i iii ii
(D) ii iii iv i
Ans: C
26. Match the List – I and List – II:
List – I List – II
(Type of counters) (No. of flip flops required)
a. Mod-6 i. 3
b. Mod-11 ii. 4
c. Mod-31 iii. 5
a b c
(A) iii ii i
(B) i ii iii
(C) ii iii i
(D) iii i ii
Ans: B
27. Match the following lists:
List – I List – II
(Units) (Quantity)
a. ps/nm/km i. Attenuation
b. dB/km ii. Magnetic field
c. cm2/v-s iii. Dispersion
d. Tesla iv. Mobility
a b c d
(A) iv i ii iii
(B) iii i ii iv
(C) iii i iv ii
(D) i iv iii ii
Ans: C
28. Match the following lists:
List – I List – II
a. DAA i. Program control instruction
b. LXI ii. Data movement instruction
c. RST iii. Interrupt instruction
d. JMP iv. Arithmetic instruction
Codes:
a b c d
(A) i ii iii iv
(B) iv ii iii i
(C) iii iv i ii
(D) ii i iii iv
Ans: B
29. Match the following lists:
List – I List – II
a. 8031 i. Multiplexer
b. 7490 ii. Demultiplexer
c. 74155 iii. Microcontroller
d. 74151 iv. Decade counter
Codes:
a b c d
(A) iii iv ii i
(B) i ii iii iv
(C) ii iii iv i
(D) iii i ii iv
Ans: A
30. Match the following lists:
List – I List – II
a. Bourdon tube i. Distance
b. Strain gauge ii. Temperature
c. Thermistor iii. Pressure
d. LVDT iv. Stress
Codes:
a b c d
(A) i ii iii iv
(B) iii iv ii i
(C) ii iii iv i
(D) i iii ii iv
Ans: B
31. Match the following lists:
List – I List – II
(Types of ADC) (Characteristics)
a. Parallel comparator (i.e. flash) type i. integrating type
b. Successive approximation ii. Fastest converter
c. Dual slope iii. Conversion time is independent of the amplitude of the analogue signal
d. Counter type iv. Uses DAC in feedback path
Codes:
a b c d
(A) ii iii i iv
(B) i ii iv iii
(C) iv iii ii i
(D) iv ii iii i
Ans: A
32. Match the following lists:
List – I List – II
a. Flip-Flop can be used as latch i. D Flip-flop
b. Flip-Flop can be used as delayed ii. Master- Slave
c. Flip-Flop does not have race problem iii. JK
d. Flip-flop can be used as shift registers iv. R-S
Codes:
a b c d
(A) iv i ii iii
(B) ii iv i iii
(C) i iii ii iv
(D) iii i iv ii
Ans: A
33. The following are features of a micro controller 8051:
(i) 4 k bytes of ROM or EPROM
(ii) 128 k bytes of data memory
(iii) Four programmable I/O ports
(iv) Three 16 bit timer/event counters.
(A) (i), (ii) and (iii)
(B) (i), (ii) and (iv)
(C) (i), (iii) and (iv)
(D) (ii), (iii) and (iv)
Ans: A
34. Identify the peripheral devices for their applications.
(a) 8155 (i) Serial Communication
(b) 8279 (ii) Timers and Counters
(c) 8253 (iii) Keyboard and display interface
(d) 8251 (iv) Additional input/output lines to processor
Codes:
(a) (b) (c) (d)
(A) (ii) (iii) (iv) (i)
(B) (iii) (iv) (i) (ii)
(C) (iv) (i) (ii) (iii)
(D) (iv) (iii) (ii) (i)
Ans: D
35. Match the following lists:
List – I List – II
a Stability of Control System (i). Oscillation in which the amplitude decreases with time.
b Unstability of Control System (ii). All roots of characteristic equation have negative real part.
c Frequency response (iii). Steady state response
d Damped Oscillation (iv) Any root of characteristic equation has a positive real part
Codes:
a b c d
(A) 4 2 3 1
(B) 2 4 3 1
(C) 2 4 1 3
(D) 4 2 1 3
Ans: B
36. Match the following lists:
List – I List – II
a. Slip i. Relaxation oscillator
b. SCR ii. Class-E chopper
c. UJT iii. Two-transistor model
d. dc drives iv. Induction motors
The correct match is
a b c d
(A) i ii iii iv
(B) iii iv i ii
(C) ii iii i iv
(D) iv iii i ii
Ans: D
37. Match the following lists:
List – I List – II
a. Intermodal dispersion i. Lasers
b. Chirp ii. SMF (Single Mode Fiber)
c. Intramodal dispersion iii. III-V group
d. Direct band gap semiconductors iv. MMF (Multimode Fiber)
The correct match is
a b c d
(A) iv i ii iii
(B) iii iv i ii
(C) ii i iii iv
(D) i ii iii iv
Ans: A
38. Match the following lists:
List – I List – II
a. LVDT i. Speed
b. Techogenerators ii. Resistance
c. Wheatstone Bridge iii. Displacement
d. Bourdon tube iv. Pressure
The correct match is given by
a b c d
(A) i ii iii iv
(B) iii i ii iv
(C) i iii ii iv
(D) iii ii i iv
Ans: B
Read the paragraph and answer the questions 39 to 43:
P-i-n photodiode contains a layer of intrinsic semi-conductor material sandwiched between p-and-n regions. The depletion layer is wholly contained within the i region. Thickness of the intrinsic region can be adjusted to produce device with optimum sensitivity and frequency response. P-i-n photodiode is most common type of depletion layer photodiode.
The other classes of photodiodes, avalanche photodiodes, are reverse-biased p-n junction diodes that are operated at voltages above the breakdown voltage. Current multiplication of electron-hole pairs generated by the incident electromagnetic radiation occurs due to avalanche process. The photo multiplication factor Mpn is defined as ratio of the multiplied photocurrent Ipm to the photocurrent Ipho at voltage below breakdown where no avalanche multiplication takes place.
39. Semiconductors are sensitive to
(A) Heat
(B) Magnetic field
(C) Light energy
(D) All of the above
Ans: D
40. Which of the following elements is a semiconductor?
(A) Germanium
(B) Copper
(C) Carbon
(D) Phosphorous
Ans: A
41. When a reverse bias is applied to a junction diode
(A) Potential barrier is lowered
(B) Majority carrier current is increased
(C) Minority carrier current is increased
(D) Potential barrier is raised
Ans: D
42. Photo-diode is reverse biased because
(A) Only one side is illuminated
(B) Majority swept are reverse biased across the function
(C) Reverse current is small as compared to photo current
(D) Reverse current is large as compared to photocurrent
Ans: C
43. Avalanche photodiodes are preferred over PIN diodes in optical communication systems because of
(A) Speed of operation
(B) Higher sensitivity
(C) Larger bandwidth
(D) Larger power handling capacity
Ans: D
Read the following paragraph and answer the questions 44 to 48:
Gunn effect is instrumental in the generation of microwave oscillations in bulk semiconductor material. The effect was exhibited by gallium arenide. The effect is a bulk property of semiconductors. If a small dc voltage is placed across a thin slice of germanium arsanide a negative resistance will manifest itself under certain conditions. The voltage gradients across the slice is increase of about 3300 v/cm, oscillations will then occurat microwave frequencies if the slice is connected to a suitably tuned circuit. The Gunn effect is independent of total voltage or current and is not effected by magnetic field, it occurs in n-type of materials only.
The PIN diode consists of a narrow layer of p-type semiconductor separated from an equally narrow layer of n type material. In PIN diode silicon tend to be the main material. The PIN diode is used for microwave power switching, limiting and modulation.
44. The transferred-electron bulk effect occurs in
(A) germanium
(B) gallium arsanide
(C) silicon
(D) metal semiconductor junction
Ans: B
45. Indicate which of the following diodes does not use negative resistance in its operation:
(A) Backward
(B) Gunn
(C) IMPATT
(D) Tunnel
Ans: A
46. Response time of PIN diode is of the order of
(A) 0.1 ns
(B) 1 ns
(C) 10 ns
(D) 1 milli.sc
Ans: B
47. PIN diode is used as
(A) sine wave modulator
(B) triangular wave modulator
(C) square wave modulator
(D) low frequency rectifier
Ans: D
48. One of the following microwave diodes is suitable for very low-power oscillator only.
(A) Tunnel
(B) Avalanche
(C) Gunn
(D) IMPATT
Ans: A
49. Arrange the following in order of increasing the input impedances:
1. BJT CE stage
2. BJT in CB stage
3. BJT in CC stage
4. CMOS
The correct sequence is given by
(A) 2, 1, 3, 4
(B) 4, 2, 1, 3
(C) 4, 3, 2, 1
(D) 3, 1, 2, 4
Ans: A
50. For finding the inverse of a z-transform:
1. Partial fraction expansion
2. Contour integration
3. Convolution
4. Power series expansion
Following is the correct sequence:
(A) 1, 2, 3, 4
(B) 1, 2, 4, 3
(C) 4, 3, 2, 1
(D) 1, 3, 4, 2
Ans: B
P-i-n photodiode contains a layer of intrinsic semi-conductor material sandwiched between p-and-n regions. The depletion layer is wholly contained within the i region. Thickness of the intrinsic region can be adjusted to produce device with optimum sensitivity and frequency response. P-i-n photodiode is most common type of depletion layer photodiode.
The other classes of photodiodes, avalanche photodiodes, are reverse-biased p-n junction diodes that are operated at voltages above the breakdown voltage. Current multiplication of electron-hole pairs generated by the incident electromagnetic radiation occurs due to avalanche process. The photo multiplication factor Mpn is defined as ratio of the multiplied photocurrent Ipm to the photocurrent Ipho at voltage below breakdown where no avalanche multiplication takes place.
39. Semiconductors are sensitive to
(A) Heat
(B) Magnetic field
(C) Light energy
(D) All of the above
Ans: D
40. Which of the following elements is a semiconductor?
(A) Germanium
(B) Copper
(C) Carbon
(D) Phosphorous
Ans: A
41. When a reverse bias is applied to a junction diode
(A) Potential barrier is lowered
(B) Majority carrier current is increased
(C) Minority carrier current is increased
(D) Potential barrier is raised
Ans: D
42. Photo-diode is reverse biased because
(A) Only one side is illuminated
(B) Majority swept are reverse biased across the function
(C) Reverse current is small as compared to photo current
(D) Reverse current is large as compared to photocurrent
Ans: C
43. Avalanche photodiodes are preferred over PIN diodes in optical communication systems because of
(A) Speed of operation
(B) Higher sensitivity
(C) Larger bandwidth
(D) Larger power handling capacity
Ans: D
Read the following paragraph and answer the questions 44 to 48:
Gunn effect is instrumental in the generation of microwave oscillations in bulk semiconductor material. The effect was exhibited by gallium arenide. The effect is a bulk property of semiconductors. If a small dc voltage is placed across a thin slice of germanium arsanide a negative resistance will manifest itself under certain conditions. The voltage gradients across the slice is increase of about 3300 v/cm, oscillations will then occurat microwave frequencies if the slice is connected to a suitably tuned circuit. The Gunn effect is independent of total voltage or current and is not effected by magnetic field, it occurs in n-type of materials only.
The PIN diode consists of a narrow layer of p-type semiconductor separated from an equally narrow layer of n type material. In PIN diode silicon tend to be the main material. The PIN diode is used for microwave power switching, limiting and modulation.
44. The transferred-electron bulk effect occurs in
(A) germanium
(B) gallium arsanide
(C) silicon
(D) metal semiconductor junction
Ans: B
45. Indicate which of the following diodes does not use negative resistance in its operation:
(A) Backward
(B) Gunn
(C) IMPATT
(D) Tunnel
Ans: A
46. Response time of PIN diode is of the order of
(A) 0.1 ns
(B) 1 ns
(C) 10 ns
(D) 1 milli.sc
Ans: B
47. PIN diode is used as
(A) sine wave modulator
(B) triangular wave modulator
(C) square wave modulator
(D) low frequency rectifier
Ans: D
48. One of the following microwave diodes is suitable for very low-power oscillator only.
(A) Tunnel
(B) Avalanche
(C) Gunn
(D) IMPATT
Ans: A
49. Arrange the following in order of increasing the input impedances:
1. BJT CE stage
2. BJT in CB stage
3. BJT in CC stage
4. CMOS
The correct sequence is given by
(A) 2, 1, 3, 4
(B) 4, 2, 1, 3
(C) 4, 3, 2, 1
(D) 3, 1, 2, 4
Ans: A
50. For finding the inverse of a z-transform:
1. Partial fraction expansion
2. Contour integration
3. Convolution
4. Power series expansion
Following is the correct sequence:
(A) 1, 2, 3, 4
(B) 1, 2, 4, 3
(C) 4, 3, 2, 1
(D) 1, 3, 4, 2
Ans: B
Read the paragraph and answer the Question Nos. 51 to 54
The field effect transistor is a semiconductor device which depends for its operation on the control of current by an electric field. There are two types of field effect transistor, the Junction Field Effect Transistor (JFET) and Metal-Oxide- Semiconductor (MOSFET) FETs operation depends upon the flow of majority carriers only. It is therefore a unipolar device. BJT is a bipolar device. FET is relatively immune to radiation and it exhibits a high input resistance tipically many mega-ohms. It is less noisy than a tube or a bipolar transistor. It exhibits no offset voltage at zero drain current, and hence makes an excellent signal chopper. FETs are more temperature stable than BJTs. JFET is three terminal devices with gate applied potential control the flow of charges from source to drain. The n-channel MOSFET consists of a lightly p-type substrate into which two highly doped n+ regions are diffused. These n+ sections, which will act as the source and drain. A thin layer of insulating SiO2 is grown over the surface of the structure and holes are cut into the oxide layer, allowing contact with the source and drain. This layer results in an extremely high input resistance.
51. The point above the drain voltage, where there is no increase in drain current in a JFET is called as
(A) Break down point
(B) Pinch off point
(C) Knee point
(D) Critical point
Ans: B
52. FET is disadvantageous in comparison with BJT because of
(A) High input impedance
(B) Low noise
(C) High gain bandwidth behaviour
(D) Current controlled behaviour
Ans: D
53. An FET is a better chopper than BJT because it has
(A) Higher series on resistance
(B) Lower input current
(C) Higher input impedance
(D) Lower off-set voltage
Ans: D
54. For an n-channel enhancement mode MOSFET the drain current
(A) Decreases with increase in drain current.
(B) Decreases with decreases in drain voltage.
(C) Increases with increase in drain voltage.
(D) Increases with decrease in gate voltage.
Ans: C
Read the paragraph and answer the questions 55 to 59:
Microwave tubes are used as microwave amplifiers and oscillators. Three general type of microwaves tubes in which third type of tubes are useful. In this tube there is an interaction between an electron and an RF field is continuous. The Travelling Wave Tube (TWT) is the prime example of this interaction. It is an amplifier whose oscillator counterpart is called Backward Wave Oscillator (BWO). Another group of tube in which a magnetic field ensures a constant electron beam – RF field interaction and this is complimented by the cross-field amplifier (CFA). Multi-cavity Klystron is used as an amplifier of microwaves and it consists of buncher cavity and cache cavity. The Reflex Klystron is a low power and low efficiency microwave oscillator. Reflex Klystron oscillator has been replaced by various semiconductor oscillators.
55. One of the following is unlikely to be used as pulsed device. It is the
(A) Multi-cavity Klystron
(B) BWO
(C) CFA
(D) TWT
Ans: B
56. One of the reason why vacuum tubes eventually fail at microwave frequencies is that their
(A) Noise figure increases
(B) Transit-time becomes too short
(C) Shunt capacitive reactance becomes too large
(D) Series inductive reactance become too small
Ans: A
57. The Multi-cavity Klystron
(A) Has a high repeller voltage to ensure a rapid transit time.
(B) Is not a good low-level amplifier because of noise.
(C) Is not suitable for pulsed operation.
(D) Needs a long transit time through the buncher cavity to ensure current modulation.
Ans: B
58. Indicate the false statement. Klystron amplifiers may use intermediate cavities to
(A) Increase the band width of the device
(B) Improve the power gain
(C) Increase the efficiency of the Klystron
(D) Prevent the oscillations that occur in two cavities Klystron
Ans: D
59. TWT is sometimes preferred to the multi-cavity Klystron amplifier because the former
(A) Is more efficient
(B) Has a greater band width
(C) Has a higher number of modes
(D) Produces a higher output power
Ans: B
Read the paragraph and answer the questions to 60 – 64:
Multiplexing is the sending of separate signals together, over the same cable or bearer simultaneously without interference. Time division multiplex is a method of interleaving in the time domain pulses belonging to different transmissions. These pulses are generally narrow and separation between successive pulses is rather wide. That being the case it is possible, provided the two ends of a link are synchronized, to use the wide spaces for pulses belonging to other transmissions. Frequency division multiplexing concerns itself with combining continuous signals. It may be thought of as an outgrowth of independent side band transmission on a much enlarged scale. As will see 12 or 16 channels are combined into a group, 5 groups into a subgroup. Each group and subgroup is then sent as a whole unit one microwave link cable or other broadband system. Continental broadband systems are then treated followed by coaxial cables, fibre optic cable, microwave links and trope scatter systems.
60. A scheme in which several channels are interleaved and then transmitted together is known as
(A) frequency-division multiplex
(B) time-division multiplex
(C) A group
(D) A subgroup
Ans: A
61. Microwave link repeaters are typically 50 km apart
(A) Because of atmospheric attenuation
(B) Because of output tube power limitations
(C) Because of earths curvature
(D) To ensure that the applied dc voltage is not excessive
Ans: C
62. Time-division multiplex
(A) Can be used with CPM only
(B) Combines five group into a super group
(C)Stacks 24 channels in adjacent frequency slots
(D) Interleaves pulses belonging to different transmissions
Ans: D
63. Broad band long distance communication was originally made possible by the advent of
(A) Geostationary satellite
(B) Repeater amplifier
(C) H.F. Radio
(D) Telegraph Cable
Ans: B
64. The number of repeaters along a co-axial cable link depends on
(A) Whether separate tubes are used for the two directions of transmission.
(B) The bandwidth of the system.
(C) The number of co-axial cables in the tube.
(D) The separation of equalizers.
Ans: B
Read the passage and answer the Question Nos. 65 to 68:
Power devices with pnpn layers such as SCR, SCS and GTO belong to thyrister series. However UJT is also a member of this group. The silicon controlled rectifier (SCR) is three terminal pnpn semiconductor switching device, which is probably most important circuit element after the diode and the transistor. An SCR can be used as a controlled switch to perform various functions such as rectification inversion and regulation of power flow. It is unidirectional power switch and being extensively used in switching ac and dc. It has capability to control power as high as 10 MW. The frequency range of its application has also been extended up to 50 kHz. SCR is a rectifier with control action. The third element called gate enables the controlled rectification gate is used to turn SCR ‘ON’ but not turn it ‘OFF’. SCR is made of Si because it has to handle high power and high temperature.
There are many advantages of SCR as a switch i.e. the switching speed is very high up to 109 operation per second and it permits control over a large current (30- 100 A) in the load by means of a small gate current of few mA. SCR has two states turn ON and turn OFF state. There are two ways to turn ON (i) keep the gate open and made the supply voltage equal to the break over voltage (ii) operate SCR with supply voltage less than break over voltage. The general methods used for turning the SCR OFF are (i) anode current interruption and (ii) force commutation. It is not advisable to turn the SCR ‘ON’ with zero gate signals.
Some of the applications of SCR are motor controls, relay controls, inverters, preventive circuits, regulated power supply and phase control. Another pnpn device have characteristic similar to that of SCR is SCS (Silicon Controlled Switch).
A device that can control ac power to the load during the positive and negative cycle of input is called ‘triac’. It is basically a diac with a gate terminal for bilateral turn ON. Gate Turn OFF (GTO) switch is one more pnpn device which can be turned ON or OFF with cathode gate. Some application of GTO is counters, pulse generators and multivibrators.
Light activated SCR (SASCR) is turned ON by the light falling on the gate. It is used as a relay, optical light controller, phase controller and motor control device.
65. If the applied voltage is increased further when an SCR is forward biased, then
(A) It becomes more forward biased.
(B) It becomes more reverse biased.
(C) It will come to ‘ON’ state.
(D) It will come to ‘OFF’ state.
Ans: C
66. Triac can be considered as
(A) Two SCRs connected in antiparallel with common gate.
(B) Two SCRs connected in parallel with common gate.
(C) Two Resisters connected in anti-parallel.
(D) Two GTOs connected in parallel with common cathode gate.
Ans: A
67. Forced commutation is employed when anode voltage is
(A) AC
(B) DC
(C) Pulsating
(D) Triangular
Ans: B
68. Diac is
(A) Two terminal bidirectional switch.
(B) Two terminal Unilateral switch.
(C) Three terminal bidirectional switch.
(D) Three terminal unilateral switch.
Ans: A
The field effect transistor is a semiconductor device which depends for its operation on the control of current by an electric field. There are two types of field effect transistor, the Junction Field Effect Transistor (JFET) and Metal-Oxide- Semiconductor (MOSFET) FETs operation depends upon the flow of majority carriers only. It is therefore a unipolar device. BJT is a bipolar device. FET is relatively immune to radiation and it exhibits a high input resistance tipically many mega-ohms. It is less noisy than a tube or a bipolar transistor. It exhibits no offset voltage at zero drain current, and hence makes an excellent signal chopper. FETs are more temperature stable than BJTs. JFET is three terminal devices with gate applied potential control the flow of charges from source to drain. The n-channel MOSFET consists of a lightly p-type substrate into which two highly doped n+ regions are diffused. These n+ sections, which will act as the source and drain. A thin layer of insulating SiO2 is grown over the surface of the structure and holes are cut into the oxide layer, allowing contact with the source and drain. This layer results in an extremely high input resistance.
51. The point above the drain voltage, where there is no increase in drain current in a JFET is called as
(A) Break down point
(B) Pinch off point
(C) Knee point
(D) Critical point
Ans: B
52. FET is disadvantageous in comparison with BJT because of
(A) High input impedance
(B) Low noise
(C) High gain bandwidth behaviour
(D) Current controlled behaviour
Ans: D
53. An FET is a better chopper than BJT because it has
(A) Higher series on resistance
(B) Lower input current
(C) Higher input impedance
(D) Lower off-set voltage
Ans: D
54. For an n-channel enhancement mode MOSFET the drain current
(A) Decreases with increase in drain current.
(B) Decreases with decreases in drain voltage.
(C) Increases with increase in drain voltage.
(D) Increases with decrease in gate voltage.
Ans: C
Read the paragraph and answer the questions 55 to 59:
Microwave tubes are used as microwave amplifiers and oscillators. Three general type of microwaves tubes in which third type of tubes are useful. In this tube there is an interaction between an electron and an RF field is continuous. The Travelling Wave Tube (TWT) is the prime example of this interaction. It is an amplifier whose oscillator counterpart is called Backward Wave Oscillator (BWO). Another group of tube in which a magnetic field ensures a constant electron beam – RF field interaction and this is complimented by the cross-field amplifier (CFA). Multi-cavity Klystron is used as an amplifier of microwaves and it consists of buncher cavity and cache cavity. The Reflex Klystron is a low power and low efficiency microwave oscillator. Reflex Klystron oscillator has been replaced by various semiconductor oscillators.
55. One of the following is unlikely to be used as pulsed device. It is the
(A) Multi-cavity Klystron
(B) BWO
(C) CFA
(D) TWT
Ans: B
56. One of the reason why vacuum tubes eventually fail at microwave frequencies is that their
(A) Noise figure increases
(B) Transit-time becomes too short
(C) Shunt capacitive reactance becomes too large
(D) Series inductive reactance become too small
Ans: A
57. The Multi-cavity Klystron
(A) Has a high repeller voltage to ensure a rapid transit time.
(B) Is not a good low-level amplifier because of noise.
(C) Is not suitable for pulsed operation.
(D) Needs a long transit time through the buncher cavity to ensure current modulation.
Ans: B
58. Indicate the false statement. Klystron amplifiers may use intermediate cavities to
(A) Increase the band width of the device
(B) Improve the power gain
(C) Increase the efficiency of the Klystron
(D) Prevent the oscillations that occur in two cavities Klystron
Ans: D
59. TWT is sometimes preferred to the multi-cavity Klystron amplifier because the former
(A) Is more efficient
(B) Has a greater band width
(C) Has a higher number of modes
(D) Produces a higher output power
Ans: B
Read the paragraph and answer the questions to 60 – 64:
Multiplexing is the sending of separate signals together, over the same cable or bearer simultaneously without interference. Time division multiplex is a method of interleaving in the time domain pulses belonging to different transmissions. These pulses are generally narrow and separation between successive pulses is rather wide. That being the case it is possible, provided the two ends of a link are synchronized, to use the wide spaces for pulses belonging to other transmissions. Frequency division multiplexing concerns itself with combining continuous signals. It may be thought of as an outgrowth of independent side band transmission on a much enlarged scale. As will see 12 or 16 channels are combined into a group, 5 groups into a subgroup. Each group and subgroup is then sent as a whole unit one microwave link cable or other broadband system. Continental broadband systems are then treated followed by coaxial cables, fibre optic cable, microwave links and trope scatter systems.
60. A scheme in which several channels are interleaved and then transmitted together is known as
(A) frequency-division multiplex
(B) time-division multiplex
(C) A group
(D) A subgroup
Ans: A
61. Microwave link repeaters are typically 50 km apart
(A) Because of atmospheric attenuation
(B) Because of output tube power limitations
(C) Because of earths curvature
(D) To ensure that the applied dc voltage is not excessive
Ans: C
62. Time-division multiplex
(A) Can be used with CPM only
(B) Combines five group into a super group
(C)Stacks 24 channels in adjacent frequency slots
(D) Interleaves pulses belonging to different transmissions
Ans: D
63. Broad band long distance communication was originally made possible by the advent of
(A) Geostationary satellite
(B) Repeater amplifier
(C) H.F. Radio
(D) Telegraph Cable
Ans: B
64. The number of repeaters along a co-axial cable link depends on
(A) Whether separate tubes are used for the two directions of transmission.
(B) The bandwidth of the system.
(C) The number of co-axial cables in the tube.
(D) The separation of equalizers.
Ans: B
Read the passage and answer the Question Nos. 65 to 68:
Power devices with pnpn layers such as SCR, SCS and GTO belong to thyrister series. However UJT is also a member of this group. The silicon controlled rectifier (SCR) is three terminal pnpn semiconductor switching device, which is probably most important circuit element after the diode and the transistor. An SCR can be used as a controlled switch to perform various functions such as rectification inversion and regulation of power flow. It is unidirectional power switch and being extensively used in switching ac and dc. It has capability to control power as high as 10 MW. The frequency range of its application has also been extended up to 50 kHz. SCR is a rectifier with control action. The third element called gate enables the controlled rectification gate is used to turn SCR ‘ON’ but not turn it ‘OFF’. SCR is made of Si because it has to handle high power and high temperature.
There are many advantages of SCR as a switch i.e. the switching speed is very high up to 109 operation per second and it permits control over a large current (30- 100 A) in the load by means of a small gate current of few mA. SCR has two states turn ON and turn OFF state. There are two ways to turn ON (i) keep the gate open and made the supply voltage equal to the break over voltage (ii) operate SCR with supply voltage less than break over voltage. The general methods used for turning the SCR OFF are (i) anode current interruption and (ii) force commutation. It is not advisable to turn the SCR ‘ON’ with zero gate signals.
Some of the applications of SCR are motor controls, relay controls, inverters, preventive circuits, regulated power supply and phase control. Another pnpn device have characteristic similar to that of SCR is SCS (Silicon Controlled Switch).
A device that can control ac power to the load during the positive and negative cycle of input is called ‘triac’. It is basically a diac with a gate terminal for bilateral turn ON. Gate Turn OFF (GTO) switch is one more pnpn device which can be turned ON or OFF with cathode gate. Some application of GTO is counters, pulse generators and multivibrators.
Light activated SCR (SASCR) is turned ON by the light falling on the gate. It is used as a relay, optical light controller, phase controller and motor control device.
65. If the applied voltage is increased further when an SCR is forward biased, then
(A) It becomes more forward biased.
(B) It becomes more reverse biased.
(C) It will come to ‘ON’ state.
(D) It will come to ‘OFF’ state.
Ans: C
66. Triac can be considered as
(A) Two SCRs connected in antiparallel with common gate.
(B) Two SCRs connected in parallel with common gate.
(C) Two Resisters connected in anti-parallel.
(D) Two GTOs connected in parallel with common cathode gate.
Ans: A
67. Forced commutation is employed when anode voltage is
(A) AC
(B) DC
(C) Pulsating
(D) Triangular
Ans: B
68. Diac is
(A) Two terminal bidirectional switch.
(B) Two terminal Unilateral switch.
(C) Three terminal bidirectional switch.
(D) Three terminal unilateral switch.
Ans: A
The following items consist of two statements, one labelled as ‘Assertion A’ and the other labelled the ‘Reason (R)’. You are to examine these two statements and decide if the Assertion (A) and the Reason (R) are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer sheet accordingly.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
69. Assertion (A): In a common base amplifier voltage gain is more than 1.
Reason (R): In a common base amplifier current gain is less than 1.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: A
70. Assertion (A): Op-Amp is used for amplification of weak signals.
Reason (R): To rectify EMG signals, precision rectifiers are used.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: B
71. Assertion (A): Gray is unweighted code.
Reason (R): Gray code is not self-complementary.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: A
72. Assertion (A): TDM and FDM accomplish the same end by different means.
Reason (R): FDM involves simpler instrumentation as compared to TDM.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: C
73. Assertion (A): Dual slope A/Dconverter is the most preferred conversion technique employed in most of the digital multimeters.
Reason (R): Dual slope A/D converter provides high accuracy while at the same time suppresses the HUM effect on the input signal.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: A
74. Assertion (A): The system of propagation in waveguides is in accordance to field theory.
Reason (R): The system of propagation in transmission line is in accordance with circuit theory.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: B
75. Assertion (A): For a function to be odd f(–x) = –f(x).
Reason (R): If a function is odd, its Fourier series only contains cosine terms.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: C
76. Assertion (A): A number of thyristors operating in parallel cannot share a common heat sink.
Reason (R): For simultaneous firing of the thyristor opto isolators may be employed in the gate driving circuit.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: D
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
69. Assertion (A): In a common base amplifier voltage gain is more than 1.
Reason (R): In a common base amplifier current gain is less than 1.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: A
70. Assertion (A): Op-Amp is used for amplification of weak signals.
Reason (R): To rectify EMG signals, precision rectifiers are used.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: B
71. Assertion (A): Gray is unweighted code.
Reason (R): Gray code is not self-complementary.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: A
72. Assertion (A): TDM and FDM accomplish the same end by different means.
Reason (R): FDM involves simpler instrumentation as compared to TDM.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: C
73. Assertion (A): Dual slope A/Dconverter is the most preferred conversion technique employed in most of the digital multimeters.
Reason (R): Dual slope A/D converter provides high accuracy while at the same time suppresses the HUM effect on the input signal.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: A
74. Assertion (A): The system of propagation in waveguides is in accordance to field theory.
Reason (R): The system of propagation in transmission line is in accordance with circuit theory.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: B
75. Assertion (A): For a function to be odd f(–x) = –f(x).
Reason (R): If a function is odd, its Fourier series only contains cosine terms.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: C
76. Assertion (A): A number of thyristors operating in parallel cannot share a common heat sink.
Reason (R): For simultaneous firing of the thyristor opto isolators may be employed in the gate driving circuit.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true and (R) is false.
(D) (A) is false and (R) is true.
Ans: D
Assertion-Reason type questions: Q. 77 to 85:
The following items consist of two statements, one labelled as ‘Assertion (A)’and the other labelled the ‘Reason (R)’. Youare to examine these two statements and decide if the Assertion (A) and the Reason (R) are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer sheet accordingly.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
77. Assertion (A): A step graded junction is formed when there is an abrupt change from acceptor ion on one side to donor ions on the other side.
Reason (R): In step graded junctions, donor and acceptor concentrations are unequal and these junctions behave as asymmetrical junctions.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: A
78. Assertion (A): For a positive real function, N(s) must not have any poles in the right half plane.
Reason (R): Re [N(jw)] ≤ 0 for all w
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: C
79. Assertion (A): In common collector amplifier, voltage gain is greater than unity and this configuration is called as Emitter follower.
Reason (R): Common collector stage is used for impedance matching as its input impedance is very large as compared to output impedance.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: D
80. Assertion (A): The TTL 54/74 ALS family has smallest delay power product.
Reason (R): Power consumption in TTL 54/74 ALS is reduced as there is decrease in resistance values and consequently current reduction.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: C
81. Assertion (A): The ‘CALL’ instruction is used to transfer program control to a subprogram or subroutine.
Reason (R): The instruction pushes the current programme counter contents on to the stack and loads the given address into the PC, and program control is transferred to the given address in the instruction.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: A
82. Assertion (A): In quadrature detectors, the two signals are said to be in quadrature if they are at 45° angle.
Reason (R): Quadrature detectors are used to demodulate the FM signals.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: D
83. Assertion (A): Silicon controlled rectifiers are PNPN devices, having gate as controlling input.
Reason (R): These devices do notwork on avalanche breakdownprinciple.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: C
84. Assertion (A): PIN diodes have wider depletion region, in order to allow light to penetrate more deeply in the semiconductor material.
Reason (R): III-V semiconductor materials are used to fabricate in order to allow shorter wavelength in the region of 400-700 nm.
ACodes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
ns: C
85. Assertion (A): The ‘DO-WHILE’ statement is used less frequently than the while statement.
Reason (R): For most applications, it is more natural to test for continuation of a loop at the beginning rather than at the end of the loop.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: A
The following items consist of two statements, one labelled as ‘Assertion (A)’and the other labelled the ‘Reason (R)’. Youare to examine these two statements and decide if the Assertion (A) and the Reason (R) are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer sheet accordingly.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
77. Assertion (A): A step graded junction is formed when there is an abrupt change from acceptor ion on one side to donor ions on the other side.
Reason (R): In step graded junctions, donor and acceptor concentrations are unequal and these junctions behave as asymmetrical junctions.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: A
78. Assertion (A): For a positive real function, N(s) must not have any poles in the right half plane.
Reason (R): Re [N(jw)] ≤ 0 for all w
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: C
79. Assertion (A): In common collector amplifier, voltage gain is greater than unity and this configuration is called as Emitter follower.
Reason (R): Common collector stage is used for impedance matching as its input impedance is very large as compared to output impedance.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: D
80. Assertion (A): The TTL 54/74 ALS family has smallest delay power product.
Reason (R): Power consumption in TTL 54/74 ALS is reduced as there is decrease in resistance values and consequently current reduction.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: C
81. Assertion (A): The ‘CALL’ instruction is used to transfer program control to a subprogram or subroutine.
Reason (R): The instruction pushes the current programme counter contents on to the stack and loads the given address into the PC, and program control is transferred to the given address in the instruction.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: A
82. Assertion (A): In quadrature detectors, the two signals are said to be in quadrature if they are at 45° angle.
Reason (R): Quadrature detectors are used to demodulate the FM signals.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: D
83. Assertion (A): Silicon controlled rectifiers are PNPN devices, having gate as controlling input.
Reason (R): These devices do notwork on avalanche breakdownprinciple.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: C
84. Assertion (A): PIN diodes have wider depletion region, in order to allow light to penetrate more deeply in the semiconductor material.
Reason (R): III-V semiconductor materials are used to fabricate in order to allow shorter wavelength in the region of 400-700 nm.
ACodes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
ns: C
85. Assertion (A): The ‘DO-WHILE’ statement is used less frequently than the while statement.
Reason (R): For most applications, it is more natural to test for continuation of a loop at the beginning rather than at the end of the loop.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(C) (A) is true but (R) is false.
(D) (A) is false and (R) is true.
Ans: A
Directions: Q. Nos. 86 to 95, the following items consist of two statements, one labelled the “Assertion (A)” and the other labelled the “Reason (R)”. You are to examine these two statements carefully and decide if the Assertion (A) and the Reason (R) are individually true and if so, whether the Reason (R) is a correct explanation of the Assertion (A). Select your answers to these items using the codes given below and mark your answer accordingly.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
86. Assertion (A): In amplifiers, it is easy to compare two powers on a Logarithmic rather than on linear scale. It is called decibel.
Reason (R): Decibel is defined as N = 10 log P2 / P1 , where P2 is output power and P1 is input power.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
87. Assertion (A): Magnetron is not cross field devices.
Reason (R): They make use of electric and magnetic fields simultaneously. The fields are perpendicular to each other.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
88. Assertion (A): TDM can be employed to transmit channels having unequal bandwidths.
Reason (R): If sampling theorem is strictly followed, any analog signal can be reconstructed back from the samples.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: B
89. Assertion (A): A NAND gate is called a Universal logic element.
Reason (R): Any logic function can be realized using NAND gates alone.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
90. Assertion (A): The stability of a control system can be determined from the location of roots of characteristic equation.
Reason (R): For stability the roots should lie on the left half of s-plane.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
91. Assertion (A): The intrinsic Fermi level of a semiconductor does not lie exactly at the middle of the energy band gap.
Reason (R): The densities of the available states in valence and conduction bands of an intrinsic semiconductor are equal.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
92. Assertion (A): The operating principle of Laser is based on stimulated emission process.
Reason (R): In coherent radiation, the emitted photons have same phase, same polarization and same direction with the incident photon.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
93. Assertion (A): A microprocessor interfaced with inputs, outputs and other peripheral devices is also called a micro controller system and is capable of controlling the process.
Reason (R): The microprocessor is a device which processes the instructions.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
94. Assertion (A): In control system design, the transfer function consists of both poles and zeros. To make the system stable, the poles plotted in Bode plot should be near to origin.
Reason (R): The zeros must be also near to origin.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
95. Assertion (A): A p-channel enhancement MOSFET based transistor can be turn on prematurely.
Reason (R): Most contaminants in MOS fabrication are mobile positively charged ions and they get trapped between the gate and the substrate in an n-channel enhancement MOSFET, whereas they are trapped on the other side of the substrate in the case of a p-channel enhancement MOSFET.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
Directions for Q. Nos. 96 to 100:
The following items consist of two statements, one labelled the “Assertion (A)” and the other labelled the “Reason (R)”. You are to examine these two statements carefully and decide if the “Assertion A” and the “Reason (R)” are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer accordingly.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
96. Assertion (A): 8421 code is weighted code.
Reason (R): 8421 code is self-complementary.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: C
97. Assertion (A): A stack is a type of non-sequential access memory system.
Reason (R): Memory stacks help in keeping track of return addresses and saving data for subroutines.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
98. Assertion (A): TEM waves exist in a waveguide.
Reason (R): Phase velocity and wave impedance for TEM waves are independent of the frequency of the waves.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
99. Assertion (A): In FSK, a binary 1 usually produces a higher carrier frequency than a binary 0.
Reason (R): FSK maintains a constant amplitude carrier.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: B
100. Assertion (A): An LTI discrete system represented by the difference equation y(n + 2) – 5y (n + 1) + 6y(n) = x(n) is unstable.
Reason (R): A system is unstable if the roots of the characteristic equation lie outside the unit circle.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
86. Assertion (A): In amplifiers, it is easy to compare two powers on a Logarithmic rather than on linear scale. It is called decibel.
Reason (R): Decibel is defined as N = 10 log P2 / P1 , where P2 is output power and P1 is input power.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
87. Assertion (A): Magnetron is not cross field devices.
Reason (R): They make use of electric and magnetic fields simultaneously. The fields are perpendicular to each other.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
88. Assertion (A): TDM can be employed to transmit channels having unequal bandwidths.
Reason (R): If sampling theorem is strictly followed, any analog signal can be reconstructed back from the samples.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: B
89. Assertion (A): A NAND gate is called a Universal logic element.
Reason (R): Any logic function can be realized using NAND gates alone.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
90. Assertion (A): The stability of a control system can be determined from the location of roots of characteristic equation.
Reason (R): For stability the roots should lie on the left half of s-plane.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
91. Assertion (A): The intrinsic Fermi level of a semiconductor does not lie exactly at the middle of the energy band gap.
Reason (R): The densities of the available states in valence and conduction bands of an intrinsic semiconductor are equal.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
92. Assertion (A): The operating principle of Laser is based on stimulated emission process.
Reason (R): In coherent radiation, the emitted photons have same phase, same polarization and same direction with the incident photon.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
93. Assertion (A): A microprocessor interfaced with inputs, outputs and other peripheral devices is also called a micro controller system and is capable of controlling the process.
Reason (R): The microprocessor is a device which processes the instructions.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
94. Assertion (A): In control system design, the transfer function consists of both poles and zeros. To make the system stable, the poles plotted in Bode plot should be near to origin.
Reason (R): The zeros must be also near to origin.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
95. Assertion (A): A p-channel enhancement MOSFET based transistor can be turn on prematurely.
Reason (R): Most contaminants in MOS fabrication are mobile positively charged ions and they get trapped between the gate and the substrate in an n-channel enhancement MOSFET, whereas they are trapped on the other side of the substrate in the case of a p-channel enhancement MOSFET.
Codes:
(A) Both (A) and (R) are correct and (R) is correct explanation of (A).
(B) Both (A) and (R) are correct, but (R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
Directions for Q. Nos. 96 to 100:
The following items consist of two statements, one labelled the “Assertion (A)” and the other labelled the “Reason (R)”. You are to examine these two statements carefully and decide if the “Assertion A” and the “Reason (R)” are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer accordingly.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
96. Assertion (A): 8421 code is weighted code.
Reason (R): 8421 code is self-complementary.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: C
97. Assertion (A): A stack is a type of non-sequential access memory system.
Reason (R): Memory stacks help in keeping track of return addresses and saving data for subroutines.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
98. Assertion (A): TEM waves exist in a waveguide.
Reason (R): Phase velocity and wave impedance for TEM waves are independent of the frequency of the waves.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: D
99. Assertion (A): In FSK, a binary 1 usually produces a higher carrier frequency than a binary 0.
Reason (R): FSK maintains a constant amplitude carrier.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: B
100. Assertion (A): An LTI discrete system represented by the difference equation y(n + 2) – 5y (n + 1) + 6y(n) = x(n) is unstable.
Reason (R): A system is unstable if the roots of the characteristic equation lie outside the unit circle.
Codes:
(A) Both (A) and (R) are true and (R) is the correct explanation of (A).
(B) Both (A) and (R) are true, but(R) is not correct explanation of (A).
(C) (A) is true, but (R) is false.
(D) (A) is false, but (R) is true.
Ans: A
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