2. SECTION – I
Straight Objective Type
This section contains multiple choice questions numbered 100. Each question has 4 choices (A), (B), (C)
and (D), out of which ONLY ONE is correct.
3. 01 Problem
This symbol represents:
a. NOR gate
b. AND gate
c. OR gate
d. NAND gate
4. 02 Problem
a
The equation of state of some gases can be expressed as P
V2
(V b) RT
Where P is the pressure, V the volume, T the absolute temperature and a and
b are constants. The dimensional formula of a is:
a. [ML5T-2]
b. [M-1L5T-2]
c. [ML-1T-2]
d. [ML-5T-2]
5. 03 Problem
A can filled with water is rotated in a vertical circle. A what must be the
minimum velocity given to the can, so that water does not fall?
a. v rg
r
b. v
g
c. 1
v
rg
d. g
v
r
6. 04 Problem
A shell is fired from a cannon velocity v at an angle θ with the horizontal
direction. At the higher point in its path, it explodes into two pieces of equal
masses .One of the pieces retraces its path to the cannon. The speed of the
other piece immediately after the explosion is:
a. 3 v cos θ
b. 2 v cos θ
c. v cos θ
d. v cos θ
7. 05 Problem
A 16 kg block moving on a frictionless horizontal surface with a velocity of 4
m/s compresses an ideal spring and ideal spring and comes to set. If the force
constant of the spring of the spring be 100 N/m, then the spring is compressed
by:
a. 1.6 m
b. 4 m
c. 6.1 m
d. 3.2 m
8. 06 Problem
A mass of 6x1024 kg is to be compressed in a sphere in such a way that the
escape velocity from the sphere is 3x108 m/s. What should be the radius of the
sphere?
(G=6.67X10-11 N-M2/kg2)
a. 9km
b. 9km
c. 9cm
d. 9mm
9. 07 Problem
A large cylindrical tank has a hole of area A at its bottom. Water is poured in the
tank by a tube of equal cross-sectional area A, ejecting water at the speed v
.Which one of the following situations will be realized?
a. No water it mean will stay in the tank
b. The water level will keep on rising
c. The water level will rise to a height v2/2g and then stop
d. The water level will oscillate weight v2/g
10. 08 Problem
A drop of mercury of radius 2 mm is spilt into 8 identical droplets. Find the
increase in surface energy. (Surface tension of mercury is 0.465 J/m2)
a. 23.4 µJ
b. 18.5 µJ
c. 26.8 µJ
d. 16.8 µJ
11. 09 Problem
A wire of length L and radius r fixed at one end and a force F applied to the other
end produces an extension l. The extension produced in another wire of the
same material of length 2L and radius 2r by a force 2F, is:
a. L
b. 2l
c. 4l
d. l/2
12. 10 Problem
A small source of sound moves on a circle as shown in the figure and an
observer is sitting on O. Let V1, V2 and V3 be the frequencies heard when the
sources are at A , B and C respectively. Then,
a. V1>V2>V3
b. V2>V3>V1
c. V1=V2>V3
d. V2>V1>V3
13. 11 Problem
x
A transverse wave is described by the equation y y0 sin2 ft
The maximum particle velocity is equal to four times the wave velocity , if:
a. y0
4
y0
b.
2
c. 2 y0
d. y0
14. 12 Problem
A particle executes a simple harmonic motion of time period T. Find the time
taken by particle to go directly from its mean position to half the amplitude.
a. T/2
b. T/4
c. T/8
d. T/12
15. 13 Problem
Two trains are moving towards each other with speeds of 20 m/s and 15 m/s
relative to the ground. The first train sounds a whistle of frequency 600 Hz, the
frequency of the whistle heard by a passenger in the second train before the
train meets is: (the speed of sound in is 340 m/s)
a. 600 Hz
b. 585 Hz
c. 645 Hz
d. 666 Hz
16. 14 Problem
Two coherent sources of different intensities send waves which interfere. The
ratio of maximum intensity to the minimum intensity is 25. The intensities of
the sources are in the ratio:
a. 25:1
b. 5:1
c. 9:4
d. 25:16
17. 15 Problem
The optical path a monochromatic light is same. If it goes through the
thickness of 4.0 cm of glass and 4.5 cm of water. If the refractive index of glass
is 1.3, the refractive index of the water is :
a. 1.30
b. 1.36
c. 1.42
d. 1.46
18. 16 Problem
A microscope is focused on a mark on a piece of paper and then a slab of glass
of thickness 3 cm and refractive index 1.5 refractive index 1.5 is placed over a
mark. How should the microscope be moved to get the mark again in focus?
a. 1 cm upward
b. 4.5 cm downward
c. 1 cm downward
d. 2 cm upward
19. 17 Problem
A thin lens made of glass of refractive index µ= 1.5 has focal length equal to 12
4
cm in air. It is now immersed in water . Its new focal length is :
3
a. 48 cm
b. 36 cm
c. 24 cm
d. 12 cm
20. 18 Problem
Two points separated by a distance of 0.1 mm can just be resolved in a
microscope when a light of a wavelength 6000 Å is used. If the light of
wavelength 4800 Å is used, the limit of resolution becomes :
a. 0.08 mm
b. 0.10 mm
c. 0.12 mm
d. 0.06 mm
21. 19 Problem
Solar radiation emitted by sun resembles that emitted by a black body at a
temperature of 6000 K. Maximum intensity is emitted at a wave length of
about 4800 Å. If the sun were to cool down from 6000 K to 300 K, then the
peak intensity would occur at a wavelength
a. 4800 Å
b. 9600 Å
c. 7200 Å
d. 6400 Å
22. 20 Problem
Air is pumped into an automobile tube upto a pressure of 200 kPa in the
morning when the air temperature is 220C. During the day temperature is 220C.
During the day, temperature rises to 420C and the tube expands by 2%. The
pressure of the air in the tube at this temperature, will be approximately :
a. 212 kPa
b. 209 kPa
c. 206 kPa
d. 200 kPa
23. 21 Problem
A block of mass 100 g slides on a rough horizontal surface. If the speed of the
block decreases from 10 m/s to 5 m/s, the thermal energy developed in the
process is :
a. 3.75 J
b. 37.5 J
c. 0.375 J
d. 0.75 J
24. 22 Problem
An ideal gas at 270C is compressed adiabatically to 8/27 of its original volume.
If γ=5/3 then the rise in temperature is :
a. 575 K
b. 450 K
c. 225 K
d. 375 K
25. 23 Problem
Two rods (one semicircular and other straight) of same material and of same
cross-sectional area are joined as shown in the figure. The points A and B are
maintained at different temperatures. The ratio of the heat transferred
through a cross-section of a semicircular rod to the heat transferred through a
cross-section of the straight rod in a given time is :
a. 2 : π
b. 1 : 2
c. π: 2
d. 3 : 2
26. 24 Problem
In the circuit shown, the heat produced in the 5 Ω resistor is 10 cal/s. the heat
generated in the 4Ω resistor is :
a. 1 cal/s
b. 2 cal/s
c. 6 cal/s
d. 8 cal/s
27. 25 Problem
A radioactive material decays by simultaneous emission of two particles with
half-lives 1620 and 810 year respectively. The time in year after which one-
fourth of the material remains, is :
a. 4860 year
b. 3240 year
c. 2340 year
d. 1080 year
28. 26 Problem
A potential barrier of 0.50 V exists across a p-n junction. If the depletion region
is 5.0 x 10-7 m wide, the intensity of the electric field in this region is :
a. 1.0 x 106 V/m
b. x 105 V/m
c. 2.0 x 105 V/m
d. 2.0 x 106 V/m
29. 27 Problem
The circuit shown in the figure contains two diodes each with a forward
resistance of 50 Ω and with finite backward resistance. If the battery of 6V, the
current through the 100 Ω resistance (in ampere) is :
a. Zero
b. 0.02
c. 0.03
d. 0.036
30. 28 Problem
If the velocity of light (c), gravitational constant (G) and Planck’s constant (h)
are chosen as fundamental units, then the dimensions of mass in new system
is :
a. c1/2G1/2h1/2
b. c1/2G1/2h - 1/2
c. c1/2G - 1/2h1/2
d. c - 1/2G1/2h1/2
31. 29 Problem
A block of mass 2 kg is suspended through two light spring balance A and B as
shown in figure. These balances A and B will respectively read :
a. 2 kg and zero
b. zero and 2 kg
c. 2 kg and 2 kg
d. 1 kg and 1 kg
32. t = t 1 – t2
30 Problem
A stone dropped from a balloon which is at a height h, reaches the ground
after t seconds. From the same balloon, if two stones are thrown, one upwards
and the other downwards, with the same velocity u and they reach the ground
after t1 and t2 seconds respectively, then :
t1 t2
a. t
2
b. t t1t2
2 2
c. t1 t2
d. t = t1 – t2
33. 31 Problem
A shell at rest at the origin exploded into three fragments of masses 1kg, 2 kg
and m kg. The 2 kg and 1 kg pieces fly off with speeds of 12 m/s along x-axis
and 16 m/s along y-axis respectively. If the m kg piece flies off with a speed of
40 m/s, the total mass of the shell must be :
a. 3.7 kg
b. 4 kg
c. 4.5 kg
d. 5 kg
34. 32 Problem
If a sphere is rolling, then the ratio at its rotational kinetic energy to the total
kinetic energy is :
a. 1 : 2
b. 2 : 5
c. 2 : 7
d. 5 : 7
35. 33 Problem
A geostationary satellite is orbiting the earth at a height of 6 R above the
surface of earth, R being the radius of earth. The time period of another
satellite at a height of 2.5 R from the surface of earth, is :
a. 10 h
b. (6/ 2 )h
c. 6 h
d. 6 2 h
36. 34 Problem
A body weights w Newton at the surface of the earth. Its weight at a height
equal to half the radius of the earth, will be :
a. w
2
2w
b.
3
c. 4w
9
8w
d. 27
37. 35 Problem
A spring of force constant k is cut into two pieces such one piece is three time
the length of the other. The longer piece will have a force constant of :
a. 3/4 k
b. 4/3 k
c. 4 k
d. 9 k
38. 36 Problem
For an ideal gas of diatomic molecules, where Cp and Cv are the two specific
heats of the gas and R the gas constant, then :
a. CP = 5/2R
b. CV = 3/2R
c. VP = CV= 2R
d. CP = 7/2 R
39. 37 Problem
The P-V diagram of a system undergoing thermodynamic transformation is
shown in figure. The work done by the system in going from is 50 J and 20 cal
heat is given to the system. In internal energy between A and C is :
a. 34 J
b. 70 J
c. 84 J
d. 134 J
40. 38 Problem
Two rods of the same length and material transfer a given amount of heat in 12
s when they are joined end to end. But when they are joined lengthwise, they
will transfer the same amount of heat, in the same conditions, in :
a. 1.5 s
b. 3 s
c. 24 s
d. 48 s
41. 39 Problem
Two identical flutes produce fundamental notes of frequency 300 Hz at 270C. If
the temperature of air at one flute is increased to 310C, the number of the
beats heard per second, will be :
a. 1
b. 2
c. 3
d. 4
42. 40 Problem
A source of sound of frequency 256 Hz is moving rapidly towards a wall with a
velocity of 5 m/s. The speed of sound is 330 m/s. If the observer is in between
the wall and the source, then beats per second heard will be :
a. 7.8 Hz
b. 9.7 Hz
c. 3.9 Hz
d. zero
43. 41 Problem
The coefficient of performance of a Carnot’s refrigerator working between
300C and 00C is :
a. 10
b. 1
c. 9
d. zero
44. 42 Problem
The equivalent capacitance in the circuit between A and B will be :
a. 1 µF
b. 2 µF
c. 3 µF
d. 1/3 1 µF
45. 43 Problem
The electric potential at a point (x, y) in the x-y plane is given by V = -kxy. The
filed intensity at a distance r from the origin varies as :
a. r2
b. r
c. 1/r
d. 1/r2
46. 44 Problem
If n drops, each of capacitance C, coalesce 10 form a single big drop, then the
ratio of the energy stored in the big drop to that in each small drop, will be :
a. n : 1
b. n1/3 : 1
c. n5/3 : 1
d. n2 : 1
47. 45 Problem
125 cm of potentiometer wire balances the emf of a cell and 100 cm of the
wire is required for balance, if the poles of the cell are joined by a 2 Ω resistor.
Then the internal resistance of the cell is :
a. 0.25 Ω
b. 0.5 Ω
c. 0.75 Ω
d. 1.25 Ω
48. 46 Problem
Three bulbs of 40 W, 60 W and 100 W are connected in series to a current
source of 200 V. Which of the following statements is true ?
a. 40 W bulb glow brightest
b. 60 W bulb glow brightest
c. 100 W bulb glow brightest
d. All bulbs glow with same brightest
49. 47 Problem
At room temperature, copper has free electron density of 8.4 x 1028/m3. the
copper conductor has a cross-section of 10-6m2 and carries a current of 5.4 A.
The electron drift velocity in copper is :
a. 400 m/s
b. 0.4 m/s
c. 0.4 m/s
d. 72 m/s
50. 48 Problem
A part of a long wire carrying a current I is bent into a circle of radius r as
shown in figure. The net magnetic field at the centre O of the circular loop is :
a. i 0
4r
i
b. 0
2r
i
c. 0
1
2 r
i
d. 0
1
2 r
51. 49 Problem
A charged particle moving with velocity v is subjected to electric field E and
magnetic filed B. The particle will go undeflected, if :
a. E is perpendicular to B
b. E is parallel to v and perpendicular to B
c. E and B both are parallel to v
d. E, B and v are mutually perpendicular but V=E/B
52. 50 Problem
A 36 Ω galvanometer is shunted by resistance of 4Ω. The percentage of the
total current, which passes through the galvanometer is :
a. 8%
b. 9%
c. 10%
d. 91%
53. 51 Problem
The meniscus of a liquid contained in one of the limbs of a narrow U-tube is
placed between the pole pieces of an electromagnet with the meniscus in line
with the field. When the electromagnet is switched on, the liquid is seen to
rise in the limb. This indicates that the liquid is :
a. Non-magnetic
b. Paramagnetic
c. Diamagnetic
d. Ferromagnetic
54. 52 Problem
Which of the following statements is incorrect about hysteresis ?
a. This effect is common to all ferromagnetic substances
b. The hysteresis loop area is proportional to the thermal energy developed
per unit volume of the material
c. The hysteresis hoop area is independent of the thermal energy developed
per unit volume of the material
d. The shape of the hysteresis loop is characteristic of the material
55. 53 Problem
A motor having an armature of resistance 2Ω is designed to operate at 220 V
mains. At full speed, it develops a back emf of 210 V. When the motor is
running at full speed, the current in the armature is :
a. 5 A
b. 105 A
c. 110 A
d. 215 A
56. 54 Problem
A helium nucleus makes full rotation in a circle of radius 0.8m in 2 s. The value
of magnetic filed B at the centre of the circle, will be : ( 0 = permeability
constnat)
19
2 x 10
a.
0
19
b. 10
0
c. 2 x 10-19 µ0
d. 10-19 µ0
57. 55 Problem
The luminous intensity of lamp which produces an luminance of 12 lux at a
distance of 5 m from it, is :
a. 4 cd
b. 60 cd
c. 300 cd
d. 720 cd
58. 56 Problem
To print a photograph from a negative, the time of exposure to light from a
lamp placed. 60 cm away is 2.5 s. If the lamp is placed 1.2m away, then the
exposure time required is :
a. 5 s
b. 10 s
c. 15 s
d. 20 s
59. 57 Problem
If two + 5D lenses are mounted at some distance apart, the equivalent power
will always be negative, if the distance is :
a. Greater than 40 cm
b. Equal to 40 cm
c. Equal to 10 cm
d. Less than 10 cm
60. 58 Problem
The population inversion necessary for laser action used in solid state lasers is :
a. Electrical discharge
b. Inelastic atom-atom collision
c. Direct conversion
d. Optical pumping
61. 59 Problem
The work of a substance is 4.0 eV. The longest wavelength of light that can
cause photoelectron emission from this substance is approximately :
a. 540 nm
b. 400 nm
c. 310 nm
d. 220 nm
62. 60 Problem
The innermost orbit of the hydrogen atom has a diameter 1.06 Å. The diameter
of tenth orbit is :
a. 5.3 Å
b. 10.6 Å
c. 5.3 Å
d. 106 Å
63. 61 Problem
Which one of the following statements about uranium is correct ?
a. 235U is fissionable by thermal neutrons
b. fast neutrons trigger the fission process in 235U
c. 238U is broken into fragments when bombarded by slow neutrons
d. 235U is an unstable isotope and undergoes spontaneous fission
64. 62 Problem
The decay constant of radioactive substances is The half-life and mean-life
.
of the substance are respectively given by :
a. 1/and (In 2/)
b. (In 2/ and 1/
)
c. 1/and (ln 2)
d. (ln 2) and 1/
65. 63 Problem
22Ne nucleus, after absorbing energy, decays into two -particles and an
unknown nucleus. The unknown nucleus is :
a. nitrogen
b. carbon
c. boron
d. oxygen
66. 64 Problem
A logic gate having two inputs A and B and output C has the following truth
table
This gate is :
a. OR
b. AND
c. NOT
d. NAND
67. 65 Problem
The given figure shows the wave forms for two inputs A and B and that for the
output Y of a logic circuit. The logic circuit is :
a. An AND gate
b. An OR gate
c. A NAND gate
d. A NOT gate
68. 66 Problem
The current voltage characteristic of a p-n junction diode is represented by the
graph :
a.
b.
c.
d.
69. 67 Problem
If L, C and R denote the inductance, capacitance and resistance respectively,
the dimensional formula for C2LR is :
a. [ML2T-1I0]
b. [M0L0T2I0]
c. [M-1L-2T6I2]
d. [M0L0T2I0]
70. 68 Problem
A cricketer can throw a ball to a maximum horizontal distance of 100 m. With
the same effort, he throws the ball vertically upwards. The maximum height
attained by the ball is :
a. 100 m
b. 80 m
c. 60 m
d. 50 m
71. 69 Problem
From the top of a tower, a particle is projected with a velocity of 19.6 m/s2, the
particle will move at right angles to its initial direction of motion after a time of
:
a. 1 s
b. 4 s
c. 6 s
d. 8 s
72. 70 Problem
A can filled with water is revolved in a vertical circle of radius 4 m and the
water does not fall down. The time period for a revolution is about :
a. 2 s
b. 4 s
c. 8 s
d. 10 s
73. 71 Problem
If boiling point of water is 950F, what will reduction at Celsius scale ?
a. 70C
b. 650C
c. 630C
d. 350C
74. 72 Problem
The centre of mass of three particles of masses 1 kg, 2 kg and 3 kg is a (3, 3, 3)
with reference to a fixed co-ordinate system. Where should a fourth particle of
mass 4 kg be placed, so that the centre of mass of the system of all particles
shifts to a point (1, 1, 1) ?
a. (-1, -1, -1)
b. (-2, -2, -2)
c. (2, 2, 2)
d. (1, 1, 1)
75. 73 Problem
A pulley fixed to the ceiling carries a string with blocks of masses m and 3 m
attached to its ends. The masses of string and pulley are negligible. When the
system is released, its centre of mass with what acceleration ?
a. Zero
b. -g/4
c. g/2
d. -g/2
76. 74 Problem
A uniform rod of length l and mass m is free to rotate in a vertical plane about
A. The rod initially in horizontal position is released. The initial angular
acceleration of the rod is :
2
(Moment of inertia of rod about A ml is ):
3
3g
a.
2l
b. 2l
3g
3g
c.
2l 2
l
d. mg
2
77. 4
75 Problem
Suppose the law of gravitational attraction suddenly changes and becomes an
1
inverse cube law, i.e. F , , but still remaining a central force. Then :
r3
a. Kepler’s law of areas still holds
b. Kepler’s law of periods still holds
c. Kepler’s law of areas and periods still holds
d. Neither the law of areas, nor the law of periods still holds
78. 4
76 Problem
Water rises in a vertical capillary tube up to a height of 2.0 cm. If the tube is
inclined at an angle of 600 with the vertical, then upto what length the water
will rise in the tube ?
a. 1.0 cm
b. 4.0 cm
c. 4 cm
3
d. 2 2 cm
79. 77 Problem
A particle of mass m is under the influence of a force F which varies with the
displacement x according to the relation F = - kx + f0 in which k and f0 are
constants. The particle when disturbed will oscillate about :
a. x = 0 with k /m
b. x = 0 with k /m
c. x = f0/k with k /m
d. x = f0/k with k /m
80. 78 Problem
A pan with set of weights is attached with a light spring. When disturbed, the
mass-spring system oscillates with a time period 0.6 s. When some additional
weights are added, then time period is 0.7 s. The extension caused by the
additional weights is approximately given by :
a. 1.38 cm
b. 3.3 cm
c. 1.75 cm
d. 2.45 cm
81. 79 Problem
Two waves represented by the following equations are traveling in the same
medium
y1 = 5 sin 2 π (75t - 25 x)
y2 = 10 sin 2 π(150t – 50 x)
The intensity ratio I1/I2 of the two waves is :
a. 1 : 2
b. 1 : 4
c. 1 : 8
d. 1 : 16
82. 80 Problem
A source of sound placed at the open end of a resonance column sends an
acoustic wave of pressure amplitude P0 inside the tube. If the atmosphere
pressure is PA, then the ratio of maximum and minimum pressure at the closed
end of the tube will be :
a. (PA + P0) / (PA – P0)
b. (PA + P0) (PA – 2P0)
c. PA,PA
d. . PA 1 P0 PA
1
P0
2 2
83. 81 Problem
Two sources S1 and S2 each emitting waves of wavelength are kept
symmetrically on either side of centre O of a circle ABCD such that S1O = S2O =
1.5 If a detector is moved along the circumference of the circle, it will record
.
how many maximas in one revolution ?
a. 8
b. 12
c. 16
d. 10
84. 82 Problem
An ideal gas expands in such a manner that its pressure and volume comply
with the condition PV2 = constant. During this process, the gas is :
a. Heated
b. Cooled
c. Neither heated nor cooled
d. First heated and then of a cooled
85. 83 Problem
Energy of all molecules of a monatomic gas having a volume V and pressure P
is 3/2 PV. The total translational kinetic energy of all molecules of a diatomic
gas at the same volume and pressure, is :
a. 1/2PV
b. 3/2PV
c. 5/2PV
d. 3 PV
86. 84 Problem
Three rods of the same dimensions have thermal conductivities 3K, 2 K and K.
They are arranged as shown in figure with their ends at 1000C, 500C and 200C.
The temperature of their junction is :
a. 600
b. 700
c. 500
d. 350
87. 85 Problem
An electron moving in a circular orbit of radius r makes n revolutions per
second. As a result the magnetic field produced at the centre is :
ne
a. B 0
2 r
n2e
b. B 0
2r
ne
c. B 0
2r
d. B = 0
88. 86 Problem
A concave mirror of a radius of curvature 1 m is placed at the bottom of a tank
of water. The mirror forms an image of the sun, when it is directly overhead.
Calculate the distance of the image from the mirror for 80 cm of water in the
tank :
a. 30 cm
b. 50 cm
c. 40 cm
d. 10 cm
89. 87 Problem
A ray PQ incident on the refracting face BA is refracted in the prism BAC as
shown in the figure and emerges from the other refracting
face AC as RS, such that AQ = AR. If the angle of prism A = 600 and the
refractive index of the material of prism is , then the angel of deviation of the
ray is:
a. 600
b. 450
c. 300
d. None of these
90. 88 Problem
When an object is moved along the axis of a convex lens, the size of image is
obtained half times the size of the object. When the object is at a distance d1
or at a distance d2 from the lens, then the focal length of the lens is:
a. d1d2
b. d1 / d2
c. 1
d1 d2
2
d. 1 d1 d2
2
91. 89 Problem
In a Galilean telescope, the inverted image formed by its objective serves as a
virtual object for its eyepiece. If the eyepiece has to from an inverted and
magnified image of the virtual object, the eyepiece has to be a concave lens
and it must be so placed that the virtual object falls:
a. Within F
b. Between F and 2F
c. At 2F
d. Beyond 2F
92. 90 Problem
In Fraunhofer diffraction pattern due to narrow slit a screen is placed 2 m away
from the lens to obtain the pattern. If the slit width is 0.2 mm on either sides
of the central maximum, the wavelength of light used is :
a. 5000 Å
b. 2000 Å
c. 1500 Å
d. 1000 Å
93. 91 Problem
In an electromagnetic field, the amplitude of magnetic field is 3 x 10-10 T. If the
frequency of the wave is 1012 Hz, then the amplitude of the associated electric
field will be :
a. 9 x 10-2 V/m
b. 3 x 10-2 V/m
c. 3 x 10-10 V/m
d. 9 V/m
94. 92 Problem
The centre of a circular table has radius r. The illuminance at the centre of the
table is eight times that at its circumference. The height of the lamp above the
table is :
a. R
b. r
2
r
c.
3
r
d.
7
95. 93 Problem
The spectral lines of Lyman series lie in which region of the spectrum ?
a. Ultraviolet
b. Visible
c. Near infrared
d. Far infrared
96. 94 Problem
For an atom, the energy level corresponding to ground state is E1, the
metastable state is E2 and an excited state above the metastable state is E3. If
the number of atoms in these states are N1, N2 and N3 respectively, then in
relation to laser action, the population inversion means that :
a. N2 < N1
b. N2 > N1
c. N3 < N3
d. N3 > N1
97. 95 Problem
An alpha particle is acceleration through a potential difference of 200 V. The
increase in its kinetic energy is :
a. 100 eV
b. 200 eV
c. 400 eV
d. 800 eV
98. 96 Problem
The rest mass of an electron as well as that of positron is 0.51 MeV. When an
electron and positron are annihilated, they produce gamma-rays of wavelength
:
a. 0.012 Å
b. 0.024 Å
c. 0.012 Å to ∞
d. 0.024 Å to ∞
99. 97 Problem
When forward bias is applied to a p-n junction, then what happens to the
potential barrier VB, and the width of charge depleted region x ?
a. VB Increases, x decreases
b. VB decreases, x increases
c. VB Increases, x increases
d. VB decreases, x decreases
100. 98 Problem
Zener breakdown in a semiconductor diode occurs when :
a. Forward current exceeds certain value
b. Reverse bias exceeds certain value
c. Forward bias is equal to certain value
d. Potential barrier is reduced to zero
101. 99 Problem
A transistor connected in common-emitter configuration has input resistance
RCE = 2 kΩ and load resistance of 5 kΩ If = 60 and an input signal 12 mV is
applied. Calculate the voltage gain, the power gain and the value of output
voltage are :
a. AV = 150, Vout = 1.8 V and power gain = 9000
b. AV = 20, Vout = 1.8 V and power gain = 2000
c. AV = 150, Vout = 1.8 V and power gain = 8500
d. AV = 20, Vout = 1.5 V and power gain = 2000
102. 100 Problem
To get an output 1 from the circuit shown in the figure, the input must be :
a. A = 0, B = 1, C = 0
b. A = 1, B = 0, C = 0
c. A = 1, B = 0, C = 1
d. A = 1, B = 1, C = 0
