PHYSICS- PAGE 7
1. Nuclear forces are in general
1) Short ranged, attractive and charge independent
2) Short ranged, attractive and spin independent
3) Short ranged, repulsive and spin independent
4) Long ranged, attractive and charge dependent.
Ans: 1
2. The masses of neutron and proton are 1.0087 u and 1.0073u respectively . If neutrons and protons combine to form a helium nucleus of mass 4.0015 u ,then the binding energy of the helium nucleus is :
1) 7.1 MeV
2) 20.2 MeV
3) 28.4 MeV
4) 36.5 MeV
Ans: 3
3. According to the liquid drop model , when a nucleus is bombarded by neutrons , the compound nucleus attains the given shapes in sequence :
1) ellipsoidal , spherical , dumbbell
2) spherical ,ellipsoidal , dumbbell
3) spherical ,dumbbell, ellipsoidal
4) dumbbell, ellipsoidal , spherical
Ans: 2
4. According to shell model :
1) Nucleons have continous energy states
2) Nucleons are held in equilibrium under symmetric nuclear forces.
3) There is no spinorbit coupling in nucleus.
4) Nucleons move independently in a central filed
Ans: 4
5. Choose the wrong statement for Leptons :
1) The spin of every lepton is 1/2 .
2) Charged leptons are negatively charged particle.
3) All leptons are stable particles.
4) All leptons are acted upon by weak forces.
Ans: 3
6. The quark structure of neutron is :
1) u u d
2) u u s
3) d d u
4) d d s
Ans: 3
7. Positronium is the bound state of an electron and a positron. The most probable decay product of any such state of positronium with zero spin is [ Consider states of zero orbital angular momentum only ]
1) 4 photon
2) 2 photon
3) 0 photon
4) 1 photon
Ans: 2
8. The technique used in mass production of integrated chips is
A) photography
B) photolithography
C) atomic force microscopy
D) holography
Ans: B
9. A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves :
a. cells
b. potential gradients
c. a condition of no current flow through the galvanometer
d. a combination of cells, galvanometer and resistances
Answer: c
10. The refractive index of glass is least for
a. red colour
b. purple colour
c. yellow colour
d. green colour
Ans: a
11:-Which is the unit of loudness of sound?
A:-Decibel
B:-Farad
C:-Volta
D:-Bar
Ans: A
1) Short ranged, attractive and charge independent
2) Short ranged, attractive and spin independent
3) Short ranged, repulsive and spin independent
4) Long ranged, attractive and charge dependent.
Ans: 1
2. The masses of neutron and proton are 1.0087 u and 1.0073u respectively . If neutrons and protons combine to form a helium nucleus of mass 4.0015 u ,then the binding energy of the helium nucleus is :
1) 7.1 MeV
2) 20.2 MeV
3) 28.4 MeV
4) 36.5 MeV
Ans: 3
3. According to the liquid drop model , when a nucleus is bombarded by neutrons , the compound nucleus attains the given shapes in sequence :
1) ellipsoidal , spherical , dumbbell
2) spherical ,ellipsoidal , dumbbell
3) spherical ,dumbbell, ellipsoidal
4) dumbbell, ellipsoidal , spherical
Ans: 2
4. According to shell model :
1) Nucleons have continous energy states
2) Nucleons are held in equilibrium under symmetric nuclear forces.
3) There is no spinorbit coupling in nucleus.
4) Nucleons move independently in a central filed
Ans: 4
5. Choose the wrong statement for Leptons :
1) The spin of every lepton is 1/2 .
2) Charged leptons are negatively charged particle.
3) All leptons are stable particles.
4) All leptons are acted upon by weak forces.
Ans: 3
6. The quark structure of neutron is :
1) u u d
2) u u s
3) d d u
4) d d s
Ans: 3
7. Positronium is the bound state of an electron and a positron. The most probable decay product of any such state of positronium with zero spin is [ Consider states of zero orbital angular momentum only ]
1) 4 photon
2) 2 photon
3) 0 photon
4) 1 photon
Ans: 2
8. The technique used in mass production of integrated chips is
A) photography
B) photolithography
C) atomic force microscopy
D) holography
Ans: B
9. A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves :
a. cells
b. potential gradients
c. a condition of no current flow through the galvanometer
d. a combination of cells, galvanometer and resistances
Answer: c
10. The refractive index of glass is least for
a. red colour
b. purple colour
c. yellow colour
d. green colour
Ans: a
11:-Which is the unit of loudness of sound?
A:-Decibel
B:-Farad
C:-Volta
D:-Bar
Ans: A
12. The change in direction of the path of light ray when it passes from one medium to another is called :
(A) Interference (B) Refraction (C) Dispersion (D) Diffraction
Ans: B
13. The least count of a micrometer is :
(A) 0.01mm (B) 0.001mm (C) 0.02mm (D) 0.002mm
Ans: A
14. Which among the following is the smallest diameter of a screw thread ?
(A) Major diameter (B) Minor diameter
(C) Internal thread diameter (D) External thread diameter
Ans: B
15. The locus of the tip of a string when it is wound or unwound around a solid keeping it always tight is a :
(A) Cycloid (B) Involute (C) Ellipse (D) Helix
Ans: B
16. The measured size of a finished part is :
(A) Actual size (B) Basic size
(C) Dimensioned size (D) Production size
Ans: A
17. Hygrometer is used to measure :
(A) temperature (B) pressure (C) specific gravity (D) humidity
Ans: D
18. pH value of an acid is :
(A) less than 7 (B) greater than 7 (C) equal to 7 (D) none of the above
Ans: A
19. Resistance of a conductor is directly proportional to :
(A) length (B) area of cross section
(C) time (D) none of the above
Ans: A
(A) Interference (B) Refraction (C) Dispersion (D) Diffraction
Ans: B
13. The least count of a micrometer is :
(A) 0.01mm (B) 0.001mm (C) 0.02mm (D) 0.002mm
Ans: A
14. Which among the following is the smallest diameter of a screw thread ?
(A) Major diameter (B) Minor diameter
(C) Internal thread diameter (D) External thread diameter
Ans: B
15. The locus of the tip of a string when it is wound or unwound around a solid keeping it always tight is a :
(A) Cycloid (B) Involute (C) Ellipse (D) Helix
Ans: B
16. The measured size of a finished part is :
(A) Actual size (B) Basic size
(C) Dimensioned size (D) Production size
Ans: A
17. Hygrometer is used to measure :
(A) temperature (B) pressure (C) specific gravity (D) humidity
Ans: D
18. pH value of an acid is :
(A) less than 7 (B) greater than 7 (C) equal to 7 (D) none of the above
Ans: A
19. Resistance of a conductor is directly proportional to :
(A) length (B) area of cross section
(C) time (D) none of the above
Ans: A
20:-A charged particle is moving in a helical path under the influence of a constant magnetic field. The initial velocity of the particle is such that the component along the magnetic field is twice the component in the plane normal to the magnetic field. What will be the ratio of the pitch to the radius of the helical path ?
A:-`pi`/2 B:-`Pi` C:-2`pi` D:-4`pi`
Ans: D
21:-A square wire loop carries a steady current I. Let R be the shortest distance from the centre to the side. What will be the magnetic field at the centre of the square loop ?
A:-`(mu_(0)I)/(piR)` B:-`(mu_(0)I)/(6piR)` C:-`(sqrt(2)mu_(0)I)/(piR)` D:-`(mu_(0)I)/(sqrt(2)piR)`
Ans: C
22:-The magnetic field at a distance R from a straight wire carrying a steady current I is proportional to
A:-I/R B:-IR C:-I/`R^(2)` D:-`I^(2)`/R
Ans: A
23:-Which of the following thermodynamic relation is correct ?
A:-dU = T dS + P dV B:-dU = T dS - P dV C:-dU = T dS + G dP D:-dU = T dS - G dP
Ans: B
24:-Which mode of electromagnetic radiation cannot propagate through a rectangular waveguide ?
A:-TE B:-TM C:-TEM D:-All the above
Ans: C
25:-Which is the least symmetric crystal system ?
A:-cubic B:-triclinic C:-orthorhombic D:-monoclinic
Ans: B
26:-The amount of split in an energy level in the case of anomalous Zeeman effect due a magnetic field B, from non field level (where `mu_(B)` is the Bohr magnetron, `m_(j)` is the magnetic total angular momentum quantum number and g is the Lande g factor) is given by
A:-`(gm_(j))/(mu_(B))B` B:-`(gmu_(B))/(m_(j))B`
C:-g`mu_(B)m_(j)B` D:-`(m_(j)mu_(B))/(g)B`
Ans: C
27:-The substances, which are expected to show electron spin resonance spectroscopy, are
A:-paramagentic B:-diamagnetic C:-ferromagnetic D:-none of these
Ans: A
28:-The selection rule governing the transition between different energy levels in pure rotational Raman spectra, in terms of rotational quantum number J, is
A:-ΔJ = 0 or `+- 1` only B:-ΔJ = `+- 1` only C:-ΔJ = 0 or `+- 2` only D:-ΔJ = `+- 2` only
Ans: C
29:-A radio wave has electric field intensity `10^(-4)` V`m^(-1)` at the location of a receiving antenna. What will be the magnetic flux density ?
A:-zero B:-3.3 `xx10^(-4)` T C:-1.1 `xx10^(-9)` T D:-3.3 `xx10^(-13)` T
Ans: D
30:-The cut off frequency of T`E_(10)` dominant mode of an air filled rectangular wave guide of dimension x = 8 cm and y = 4 cm is 1875 MHz. What will be the cut off frequency of the T`E_(10)` dominant mode for another wave guide of dimension x = 8cm and y = 6 cm ? A:-1875 MHz B:-1945 MHz C:-707 MHz D:-1947 MHz
Ans: A
31:-The ratio of the electric field vector E and magnetic field vector H has the dimension of
A:-current B:-resistance C:-inductance D:-capacitance
Ans: B
32:-For the reverse leakage current of a BJT in CB (`I_(CBO)` ) and CE(`I_(CEO)` ) configuration, which among the following statements is true ?
A:-`I_(CBO)` > `I_(CEO)` B:-`I_(CBO)` = `I_(CEO)` C:-`I_(CBO)` < `I_(CEO)` D:-none of these
Ans: C
33:-With a 1 MHz clock frequency, eight bits can be parallel entered into a shift register in
A:-8`mus` B:-propagation delay time of eight flip flops
C:-propagation delay time of one flip flop D:-1`mus`
Ans: C
34:-For an ideal OPAMP integrator circuit, the peak value of output voltage
A:-is independent of frequency of the signal B:-decreases with frequency of the signal
C:-increases with frequency of the signal D:-decreases with amplitude of the signal
Ans: B
35:-In a 4 bit R-2R ladder digital to analog converter, R = 10kΩ and `V_(ref)` is 10V. The current resolution of the converter is
A:-10.5 `muA` B:-50.25 `muA` C:-62.5 `muA` D:-6.25`muA`
Ans: C
36:-In the expression for the binding energy of a nucleus according to the liquid drop model, which among the following terms arises due to Pauli's exclusion principle ?
A:-volume term B:-surface term C:-pairing term D:-asymmetry term
Ans: D
37:-The strangeness quantum number S, in the Quark Model for up (u) and down (d) quarks are
A:-zero for both u and d B:-+1 for both u and d C:--1 for both u and d D:--1 for u and +1 for d
Ans: A
38:-The relation between the Einstein coefficients `A_(21)` and `B_(21)` is
A:-`(A_(21))/(B_(21))` = 1 B:-`(A_(21))/(B_(21))` = `(1)/(2)` C:-`(A_(21))/(B_(21))` = `(8pihv^(2))/(c^(2))` D:-`(A_(21))/(B_(21))` = `(8pihv^(3))/(c^(3))`
Ans: D
39:-In a canonical ensemble, the elements differ in their
A:-volume B:-energy C:-temperature D:-number of particles
Ans: B
40:-The Halmholtz free energy F, absolute temperature T and partition function Z of a canonical ensemble are related as
A:-F = - kT ln Z B:-F = kT ln Z C:-F = - kTZ D:-F = kTZ
Ans: A
41:-The mass defect per nucleon is called
A:-packing fraction B:-quadrupole moment C:-angular momentum D:-binding energy
Ans: A
42:-In how many directions, the electrons in a quantum dot are confined ?
A:-1 B:-2 C:-3 D:-4
Ans: C
43:-The energy versus wave vector graph of an electron in free space is a
A:-Straight line B:-parabola C:-hyperbola D:-circle
Ans: A
44:-The bandgap energy of GaAs is about
A:-0.42 eV B:-1.42 eV C:-0.42 keV D:-1.42 keV
Ans: B
45:-The light emission mechanism in LED is
A:-electroluminescence B:-photoluminescence C:-chemiluminescence D:-thermoluminescence
Ans: A
46:-In a first order phase transition, which among the following statements is true ?
A:-volume is continuous at the boundary B:-entropy is continuous at the boundary
C:-entropy is discontinuous at the boudnary D:-a latent heat is not involved
Ans: C
47:-The chemical potential of a photon gas is
A:-infinity B:-finite C:-imaginary D:-zero
Ans: D
48:-When a particle of rest mass m attains the velocity of light, its mass becomes
A:-zero B:-m C:-infinity D:-2m
Ans: C
49:-For a conservative system, the slop of the potential energy versus position curve gives
A:-kinetic energy B:-force C:-power D:-momentum
Ans: B
50:-Are two simultaneous events, happening at the same point, simultaneous in all inertial frames ?
A:-yes B:-no C:-depends on the velocity of the frames D:-none of these
Ans: A
51:-The critical field of a superconductor at the critical temperature is
A:-inifinity B:-zero C:-finite D:-depends on the superconductor
Ans: B
52:-In a C60 fullerence molecule, how many pentagonal sides exist ?
A:-24 B:-6 C:-20 D:-12
Ans: D
53:-The open circuit voltage of a solar cell
A:-Increases with temperature first and then decreases
B:-decreases with temperature first and then increases
C:-Decreases with temperature
D:-Increases with temperature
Ans: C
54:-The bandwidth of an amplifier is the range of frequencies at the limits of which its voltage gain falls by _____ from the maximum gain. A:-1 dB B:-3 dB C:-9 dB D:-70 dB
Ans: B
55:-Which transistor configuration is commonly used for impedance matching ?
A:-common emitter B:-common base C:-common collector D:-common mode
Ans: C
56:-What is the hybridization in graphene ?
A:-sp B:-sp2 C:-sp3 D:-sp4
Ans: B
57:-What happens to the X-ray diffraction peaks from a polycrystalline solid, when its crystalline size decreases ?
A:-become broad B:-become narrow C:-no effect D:-disappears
Ans: A
58:-The fundamental effect that is used in the conversion of solar energy to heat energy is
A:-Photovoltaic effect B:-Faraday effect C:-Joule-Kelvin effect D:-Green house effect
Ans: D
59:-In biomass, the solar energy is stored in the form of
A:-electrical energy B:-heat energy C:-chemical energy D:-mechanical energy
Ans: C
60:-the dimensional of the phase space of a particle moving in a plane is
A:-4 B:-1 C:-2 D:-0
Ans: A
61:-Which among the following is an elementary particle ?
A:-neutron B:-kaon C:-electron D:-sigma
Ans: C
62:-The sodium D lines arise due to the transitions
A:-from P state to S state B:-from F state to S state C:-from F state to D state D:-from D state to S state
Ans: A
63:-The departure of relative permeability from unity is called
A:-Magnetic field strength B:-Magnetic susceptibility C:-Magnetic flux density D:-Magnetizing field intensity
Ans: B
64:-If the Hall co-efficient of a specimen is positive, the current conduction in the specimen is dominated by
A:-electrons B:-phonons C:-photons D:-holes
Ans: D
A:-`pi`/2 B:-`Pi` C:-2`pi` D:-4`pi`
Ans: D
21:-A square wire loop carries a steady current I. Let R be the shortest distance from the centre to the side. What will be the magnetic field at the centre of the square loop ?
A:-`(mu_(0)I)/(piR)` B:-`(mu_(0)I)/(6piR)` C:-`(sqrt(2)mu_(0)I)/(piR)` D:-`(mu_(0)I)/(sqrt(2)piR)`
Ans: C
22:-The magnetic field at a distance R from a straight wire carrying a steady current I is proportional to
A:-I/R B:-IR C:-I/`R^(2)` D:-`I^(2)`/R
Ans: A
23:-Which of the following thermodynamic relation is correct ?
A:-dU = T dS + P dV B:-dU = T dS - P dV C:-dU = T dS + G dP D:-dU = T dS - G dP
Ans: B
24:-Which mode of electromagnetic radiation cannot propagate through a rectangular waveguide ?
A:-TE B:-TM C:-TEM D:-All the above
Ans: C
25:-Which is the least symmetric crystal system ?
A:-cubic B:-triclinic C:-orthorhombic D:-monoclinic
Ans: B
26:-The amount of split in an energy level in the case of anomalous Zeeman effect due a magnetic field B, from non field level (where `mu_(B)` is the Bohr magnetron, `m_(j)` is the magnetic total angular momentum quantum number and g is the Lande g factor) is given by
A:-`(gm_(j))/(mu_(B))B` B:-`(gmu_(B))/(m_(j))B`
C:-g`mu_(B)m_(j)B` D:-`(m_(j)mu_(B))/(g)B`
Ans: C
27:-The substances, which are expected to show electron spin resonance spectroscopy, are
A:-paramagentic B:-diamagnetic C:-ferromagnetic D:-none of these
Ans: A
28:-The selection rule governing the transition between different energy levels in pure rotational Raman spectra, in terms of rotational quantum number J, is
A:-ΔJ = 0 or `+- 1` only B:-ΔJ = `+- 1` only C:-ΔJ = 0 or `+- 2` only D:-ΔJ = `+- 2` only
Ans: C
29:-A radio wave has electric field intensity `10^(-4)` V`m^(-1)` at the location of a receiving antenna. What will be the magnetic flux density ?
A:-zero B:-3.3 `xx10^(-4)` T C:-1.1 `xx10^(-9)` T D:-3.3 `xx10^(-13)` T
Ans: D
30:-The cut off frequency of T`E_(10)` dominant mode of an air filled rectangular wave guide of dimension x = 8 cm and y = 4 cm is 1875 MHz. What will be the cut off frequency of the T`E_(10)` dominant mode for another wave guide of dimension x = 8cm and y = 6 cm ? A:-1875 MHz B:-1945 MHz C:-707 MHz D:-1947 MHz
Ans: A
31:-The ratio of the electric field vector E and magnetic field vector H has the dimension of
A:-current B:-resistance C:-inductance D:-capacitance
Ans: B
32:-For the reverse leakage current of a BJT in CB (`I_(CBO)` ) and CE(`I_(CEO)` ) configuration, which among the following statements is true ?
A:-`I_(CBO)` > `I_(CEO)` B:-`I_(CBO)` = `I_(CEO)` C:-`I_(CBO)` < `I_(CEO)` D:-none of these
Ans: C
33:-With a 1 MHz clock frequency, eight bits can be parallel entered into a shift register in
A:-8`mus` B:-propagation delay time of eight flip flops
C:-propagation delay time of one flip flop D:-1`mus`
Ans: C
34:-For an ideal OPAMP integrator circuit, the peak value of output voltage
A:-is independent of frequency of the signal B:-decreases with frequency of the signal
C:-increases with frequency of the signal D:-decreases with amplitude of the signal
Ans: B
35:-In a 4 bit R-2R ladder digital to analog converter, R = 10kΩ and `V_(ref)` is 10V. The current resolution of the converter is
A:-10.5 `muA` B:-50.25 `muA` C:-62.5 `muA` D:-6.25`muA`
Ans: C
36:-In the expression for the binding energy of a nucleus according to the liquid drop model, which among the following terms arises due to Pauli's exclusion principle ?
A:-volume term B:-surface term C:-pairing term D:-asymmetry term
Ans: D
37:-The strangeness quantum number S, in the Quark Model for up (u) and down (d) quarks are
A:-zero for both u and d B:-+1 for both u and d C:--1 for both u and d D:--1 for u and +1 for d
Ans: A
38:-The relation between the Einstein coefficients `A_(21)` and `B_(21)` is
A:-`(A_(21))/(B_(21))` = 1 B:-`(A_(21))/(B_(21))` = `(1)/(2)` C:-`(A_(21))/(B_(21))` = `(8pihv^(2))/(c^(2))` D:-`(A_(21))/(B_(21))` = `(8pihv^(3))/(c^(3))`
Ans: D
39:-In a canonical ensemble, the elements differ in their
A:-volume B:-energy C:-temperature D:-number of particles
Ans: B
40:-The Halmholtz free energy F, absolute temperature T and partition function Z of a canonical ensemble are related as
A:-F = - kT ln Z B:-F = kT ln Z C:-F = - kTZ D:-F = kTZ
Ans: A
41:-The mass defect per nucleon is called
A:-packing fraction B:-quadrupole moment C:-angular momentum D:-binding energy
Ans: A
42:-In how many directions, the electrons in a quantum dot are confined ?
A:-1 B:-2 C:-3 D:-4
Ans: C
43:-The energy versus wave vector graph of an electron in free space is a
A:-Straight line B:-parabola C:-hyperbola D:-circle
Ans: A
44:-The bandgap energy of GaAs is about
A:-0.42 eV B:-1.42 eV C:-0.42 keV D:-1.42 keV
Ans: B
45:-The light emission mechanism in LED is
A:-electroluminescence B:-photoluminescence C:-chemiluminescence D:-thermoluminescence
Ans: A
46:-In a first order phase transition, which among the following statements is true ?
A:-volume is continuous at the boundary B:-entropy is continuous at the boundary
C:-entropy is discontinuous at the boudnary D:-a latent heat is not involved
Ans: C
47:-The chemical potential of a photon gas is
A:-infinity B:-finite C:-imaginary D:-zero
Ans: D
48:-When a particle of rest mass m attains the velocity of light, its mass becomes
A:-zero B:-m C:-infinity D:-2m
Ans: C
49:-For a conservative system, the slop of the potential energy versus position curve gives
A:-kinetic energy B:-force C:-power D:-momentum
Ans: B
50:-Are two simultaneous events, happening at the same point, simultaneous in all inertial frames ?
A:-yes B:-no C:-depends on the velocity of the frames D:-none of these
Ans: A
51:-The critical field of a superconductor at the critical temperature is
A:-inifinity B:-zero C:-finite D:-depends on the superconductor
Ans: B
52:-In a C60 fullerence molecule, how many pentagonal sides exist ?
A:-24 B:-6 C:-20 D:-12
Ans: D
53:-The open circuit voltage of a solar cell
A:-Increases with temperature first and then decreases
B:-decreases with temperature first and then increases
C:-Decreases with temperature
D:-Increases with temperature
Ans: C
54:-The bandwidth of an amplifier is the range of frequencies at the limits of which its voltage gain falls by _____ from the maximum gain. A:-1 dB B:-3 dB C:-9 dB D:-70 dB
Ans: B
55:-Which transistor configuration is commonly used for impedance matching ?
A:-common emitter B:-common base C:-common collector D:-common mode
Ans: C
56:-What is the hybridization in graphene ?
A:-sp B:-sp2 C:-sp3 D:-sp4
Ans: B
57:-What happens to the X-ray diffraction peaks from a polycrystalline solid, when its crystalline size decreases ?
A:-become broad B:-become narrow C:-no effect D:-disappears
Ans: A
58:-The fundamental effect that is used in the conversion of solar energy to heat energy is
A:-Photovoltaic effect B:-Faraday effect C:-Joule-Kelvin effect D:-Green house effect
Ans: D
59:-In biomass, the solar energy is stored in the form of
A:-electrical energy B:-heat energy C:-chemical energy D:-mechanical energy
Ans: C
60:-the dimensional of the phase space of a particle moving in a plane is
A:-4 B:-1 C:-2 D:-0
Ans: A
61:-Which among the following is an elementary particle ?
A:-neutron B:-kaon C:-electron D:-sigma
Ans: C
62:-The sodium D lines arise due to the transitions
A:-from P state to S state B:-from F state to S state C:-from F state to D state D:-from D state to S state
Ans: A
63:-The departure of relative permeability from unity is called
A:-Magnetic field strength B:-Magnetic susceptibility C:-Magnetic flux density D:-Magnetizing field intensity
Ans: B
64:-If the Hall co-efficient of a specimen is positive, the current conduction in the specimen is dominated by
A:-electrons B:-phonons C:-photons D:-holes
Ans: D
65.In insulators (C.B. is conduction band and V.B. is valence band)
A)V.B. is partially filled with electrons
B)C.B. is partially filled with electrons
C)C.B. is empty and V.B. is filled with electrons
D)C.B. is filled with electrons and V.B. is empty
Ans: C
66.In common base circuit of a transistor, current amplification factor is 0.95. Calculate theemitter current if base current is 0.2 mA
A)2 mA
B)4 mA
C)6 mA
D)8 mA
Ans: B
67.Gases exert pressure on the walls of the container because the gas molecules
A)have finite volume
B)obey Boyle’s law
C)possess momentum
D)collide with one another
Ans: C
68.In electromagnetic wave, according to Maxwell, changing electric field gives
A)stationary magnetic field
B)conduction current
C)eddy current
D)displacement current
Ans: D
69.A body at rest starts sliding from top of a smooth inclined plane and requires 4 second to reach bottom. How much time does it take, starting from rest at top, to cover one-fourth of a distance ?
A)1 second
B)2 second
C)3 second
D)4 second
Ans: B
70.A plane sound wave travelling with velocity ‘v’ in a medium A reaches a point on the interface of medium A and medium B. If velocity of sound in medium B is 2v, the angle of incidence for total internal reflection of the wave will be greater than (sin 30° = 0.5 and sin 90° = 1)
A)15°
B)30°
C)45°
D)90°
Ans: B
71.A gas is compressed isothermally. The r.m.s. velocity of its molecules
A)increases
B)decreases
C)first increases and then decreases
D)remains the same
Ans: D
72.Electromagnets are made of soft iron because soft iron has
A)high susceptibility and low retentivity
B)low susceptibility and high retentivity
C)low susceptibility and low retentivity
D)high susceptibility and high retentivity
Ans: A
73.The masses of three copper wires are in the ratio 1 : 3 : 5 and their lengths are in the ratio5 : 3 : 1. The ratio of their resistance is
A)25 : 1: 125
B)1 : 125 : 25
C)125 : 1 : 25
D)125 : 25 : 1
Ans: D
74.A small metal ball of mass ‘m’ is dropped in a liquid contained in a vessel, attains a terminal velocity ‘v’. If a metal ball of same material but of mass ‘8m’ is dropped in same liquid then the terminal velocity will be
A)V
B)2V
C)4V
D)8
Ans: C
75. An iron ball is heated. The percentage increase will be largest in its--
(A) Diameter
(B) Surface area
(C) Volume
(D) Density
Ans: C
76. If a magnet is cut into two pieces of equal length--
(A) Both pieces will lose their magnetism
(B) One piece will act as a North pole and the other as a South pole
(C) One of the pieces will lose its magnetism
(D) Both the pieces will behave as complete magnets
Ans: D
77. Sound travels fastest in--
(A) Air
(B) Liquid
(C) Metal
(D) Vacuum
Ans: C
A)V.B. is partially filled with electrons
B)C.B. is partially filled with electrons
C)C.B. is empty and V.B. is filled with electrons
D)C.B. is filled with electrons and V.B. is empty
Ans: C
66.In common base circuit of a transistor, current amplification factor is 0.95. Calculate theemitter current if base current is 0.2 mA
A)2 mA
B)4 mA
C)6 mA
D)8 mA
Ans: B
67.Gases exert pressure on the walls of the container because the gas molecules
A)have finite volume
B)obey Boyle’s law
C)possess momentum
D)collide with one another
Ans: C
68.In electromagnetic wave, according to Maxwell, changing electric field gives
A)stationary magnetic field
B)conduction current
C)eddy current
D)displacement current
Ans: D
69.A body at rest starts sliding from top of a smooth inclined plane and requires 4 second to reach bottom. How much time does it take, starting from rest at top, to cover one-fourth of a distance ?
A)1 second
B)2 second
C)3 second
D)4 second
Ans: B
70.A plane sound wave travelling with velocity ‘v’ in a medium A reaches a point on the interface of medium A and medium B. If velocity of sound in medium B is 2v, the angle of incidence for total internal reflection of the wave will be greater than (sin 30° = 0.5 and sin 90° = 1)
A)15°
B)30°
C)45°
D)90°
Ans: B
71.A gas is compressed isothermally. The r.m.s. velocity of its molecules
A)increases
B)decreases
C)first increases and then decreases
D)remains the same
Ans: D
72.Electromagnets are made of soft iron because soft iron has
A)high susceptibility and low retentivity
B)low susceptibility and high retentivity
C)low susceptibility and low retentivity
D)high susceptibility and high retentivity
Ans: A
73.The masses of three copper wires are in the ratio 1 : 3 : 5 and their lengths are in the ratio5 : 3 : 1. The ratio of their resistance is
A)25 : 1: 125
B)1 : 125 : 25
C)125 : 1 : 25
D)125 : 25 : 1
Ans: D
74.A small metal ball of mass ‘m’ is dropped in a liquid contained in a vessel, attains a terminal velocity ‘v’. If a metal ball of same material but of mass ‘8m’ is dropped in same liquid then the terminal velocity will be
A)V
B)2V
C)4V
D)8
Ans: C
75. An iron ball is heated. The percentage increase will be largest in its--
(A) Diameter
(B) Surface area
(C) Volume
(D) Density
Ans: C
76. If a magnet is cut into two pieces of equal length--
(A) Both pieces will lose their magnetism
(B) One piece will act as a North pole and the other as a South pole
(C) One of the pieces will lose its magnetism
(D) Both the pieces will behave as complete magnets
Ans: D
77. Sound travels fastest in--
(A) Air
(B) Liquid
(C) Metal
(D) Vacuum
Ans: C