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1. AMU PAST PAPERSPHYSICS- UNSOLVED PAPER - 2002
2. SECTION I Single Correct Answer Type There are five parts in
this question. Four choices are given for each part and one of them
is correct. Indicate you choice of the correct answer for each part
in your answer-book by writing the letter (a), (b), (c) or (d)
whichever is appropriate
3. 01 Problem Suitable impurities are added to a semiconductor
depending on its use. This is due to : a. Increase its electrical
resistivity b. Increase its electrical conductivity c. Increase its
life d. Enable it to tolerate higher voltage
4. 02 Problem When are electron and a position at rest are
annihilated, then the number of photons produced is : a. One b. Two
c. Four d. Any arbitray number
5. 03 Problem A convex lens of focal length 20 cm produces a
real image twice the size of the object. Then the distance of the
object from the lens is : a. 10 cm b. 20 cm c. 30 cm d. 40 cm
6. 04 Problem The separation between the plates of a parallel
plate capacitor is d and area of each plate is A, when a slab of
material of dielectric constant K and thickness t is introduced
between the plates, the capacitance becomes : 0 A 1 a. d t 1 K 0 A
1 b. d t 1 K 0 A 1 d t 1 c. K 0 A 1 d t 1 d. K
7. 05 Problem When a potential difference V is applied across a
conductor at temperature T, the thermal speed of electrons is
proportional to : a. T b. T c. V d. O
8. 06 Problem If the electron in hydrogen atom jumps from third
orbit to second orbit, the wavelength of the emitted radiation is
given by a. 36 5R 56 b. 3R 5 c. R R d. 6
9. 07 Problem In Youngs double slit experiment, the fringe
width is found to be 0.4 mm. If the whole apparatus is dipped in
water of refractive index 4/3, without disturbing the arrangement,
the new fringe width will be : a. 0.30 mm b. 0.40 mm c. 0.53 mm d.
0.2 m
10. 08 Problem The final image formed by a microscope is : a.
Virtual and magnified b. Real and magnified c. Real and diminished
d. Virtual and diminished
11. 09 Problem A 10 thick wire is stretched so that its length
becomes 3 times. Then the new resistance of the wire is : a. 10 b.
30 c. 90 10 d. 9
12. 10 Problem Five resistance have been connected in the
manner shown in figure. The equivalent resistance between points X
and Y will be equal to : a. 10 b. 20 c. 60 20 d. 3
13. 11 Problem Eddy currents may be reduced by using : a.
Laminated cores of steel b. Laminated core of soft iron c. Thick
piece of cobalt d. Thick piece of nickel
14. 12 Problem The magnetic energy stored in an inductor coil
varies with magnetic field a. B b. B2 1 c. B d. B0
15. 13 Problem The specific resistance of wire : a. Varies with
its length b. Varies with its cross section c. Varies with its mass
d. Is independent of length, cross section and mass of the
wire
16. 14 Problem Retentively is maximum for : a. Steel b. Soft
iron c. Copper d. Silver
17. 15 Problem The charactivity is maximum for: a. Amplitude b.
Velocity c. Frequency d. wavelength
18. 16 Problem The focal length of a concave mirror is : a.
Maximum for red colour b. Maximum for violet colour c. Maximum for
yellow colour d. Same for all colours
19. 17 Problem A force F is applied on a body and it moves with
a velocity , the power will be : a. F. F b. c. F. 2 F d. 2
20. 18 Problem For the same kinetic energy, the momentum is
maximum for : a. An electron b. A proton c. A deutron d. An
particle
21. 19 Problem Four spheres each of diameter 2a and mass M are
placed with their centers on the four corners of a square of side
b. The moment of inertia of the system about any side of the square
will be : 8 a. 5 Ma2 + 2Mb2 8 b. 5 Ma2 + Mb2 8 c. 5 Ma2 + 4Mb2 d. 8
Ma2 + 16Mb2 5
22. 20 Problem A ring of radius r and mass m rotates about an
axis passing through its centre and perpendicular to its plane, its
kinetic energy is : a. mr b. 1 mr 2 2 c. mr2 2 1 d. 2 mr2 2
23. 21 Problem If the speed of the rotation of earth increases,
then the weight of the body. a. Increases b. Decreases c. Remains
unchanged d. May increases or decrease
24. 22 Problem An organ pipe P1 closed at one end and vibrating
in its first overtone and another pipe P2 open at both ends
vibrating in its second overtone are in resonances. The ratio of
length of pipes P1 and P2 is : a. 1 b. 1/2 c. 1/3 d. 3/4
25. 23 Problem The equation of a wave traveling in a string is
given as y = 3 cos (100t -x). Its wavelength is : a. 3 cm b. 100 cm
c. 2 cm d. 5 cm
26. 24 Problem A star is moving away from the earth with a
velocity of 105 m/s. The shift in the spectral line of wavelength
5700 as observed on the earth is : a. 0.75 b. 1.75 c. 1.9 d.
2.01
27. 25 Problem Two sound wave are y a sin t kx y a cos(t kx) ,
the phase difference between the two waves is : a. /2 b. /4 c. d.
0
28. 26 Problem The velocity of sound in air is not affected by
changes in : a. Moisture contents in air b. Temperature of air c.
The atmospheric pressure d. The composition of air
29. 27 Problem The velocity of light in a medium of refractive
index 3/2 is : a. 2 x 108 m/s b. 4 x 108 m/s c. 5 x 105 m/s d. 9 x
105 m/s
30. 28 Problem The image formed by a convex mirror is : a.
Virtual, erect and diminished b. Virtual, erect and enlarged c.
Real, inverted and diminished d. Real, inverted and enlarged
31. 29 Problem In a reflecting astronomical telescope,
parabolic mirrors are used because they are free from : a.
Spherical aberration b. Chromatic aberration c. Spherical and
chromatic aberration both d. No aberration
32. 30 Problem To remove the chromatic aberration, combination
of lens should be such that : a. FR + FV = 0 b. RR + FV c. FR <
FV d. FR FV = 0
33. 31 Problem For a long cylindrical source of light, the
illuminance E on a screen varies with distance r as : a. E r-2 b. E
r-1 c. E r0 d. E r2
34. 32 Problem The radius of curvature of curved surface of a
plano-convex lens is 15 cm and refractive index of lens material is
1.6. The power of the lens will be : a. 1.66 D b. 4 D c. - 1.0 D d.
- 3.75 D
35. 33 Problem A beam of monochromatic blut light of wavelength
4200 in air travels in water (refractive index 4/3) its wavelength
in water will be : a. 2800 b. 3150 c. 4000 d. 5600
36. 34 Problem Rays of light fall on a glass plate of
refractive index . If the angle between reflected and refracted
rays is 900, then the angel of incidence is : a. sin-1( ) b. cos-1(
) c. tan-1( ) d. tan-1(1/ )
37. 35 Problem A plane glass slab is placed over letters of
different colours which letters appears to be raised most : a. Red
b. Violet c. Yellow d. All coloured letters appear equally
raised
38. 36 Problem When an ideal gas is heated at constant
pressure, the fraction of the heat energy supplied, which increases
the internal energy of the gas, is : 2 a. 5 3 b. 5 3 c. 7 5 d.
7
39. 37 Problem The second law of thermodynamics is concerned
with the : a. Conservation of energy b. Conservation of number of
holes c. Transformation of heat energy into work d. Conservation of
temperature
40. 38 Problem At which of the following temperature would the
molecules of a gas have twice, the average kinetic energy they have
at 200C ? a. 3130C b. 3730C c. 3930C d. 5860C
41. 39 Problem An iron piece falls from a height of 1 km on the
ground. If all the energy is converted into heat, the temperature
of the iron piece will be (specific heat of iron = 0.1kcal/kg 0C) :
a. 0.2330C b. 2.330C c. 32.80C d. 2330C
42. 40 Problem If a given mass of gas occupies a volume 100m3
at one atmospheric pressure and temperature of 1000C, What will be
its volume at 4 atmospheric pressure the temperature being the same
: a. 25 cm3 b. 0 c. 50 cm3 d. 5 cm3
43. 41 Problem Work done by a system is zero in : a. Isothermal
process b. Adiabatic process c. Isochoric process d. Isobaric
process
44. 42 Problem 1 mole of a monoatomic gas is first heated at
constant volume at 1000C. The change in internal energy of the gas
is u1. Next it is heated at constant pressure at 1000C, the change
in internal energy of the gas is U2. Then the u1 ratio : u2 a. 1 3
b. 5 5 c. 3 d. uncertain
45. 43 Problem If the degrees of freedom of a gas are f then
the ratio of its specific heats C p is C given by : 2 a. 1+ f b. 1
- 2 f c. 1 + 1 f 1 d. 1- f
46. 44 Problem In bringing an electron towards another
electron, electrostatic potential energy of system : a. Decreases
b. Increases c. Remains unchanged d. Becomes zero
47. 45 Problem Viscosity is most closely related to : a.
Friction b. Adhesive molecular force c. Cohesive molecular force d.
Bernoullis theorem
48. 46 Problem The substances which are repelled by a magnet
are called : a. Diamagnetic substances b. Paramagnetic substances
c. Ferromagnetic substance d. Super magnetic substance
49. 47 Problem The time constant of L-R circuit is : a. LR L b.
R R c. L 1 d. LR
50. 48 Problem In a full wave rectifier, the rms value of AC
component of the waves : a. Equal to DC value b. More than DC value
c. Less than DC value d. Zero
51. 49 Problem The minimum wavelength of X-rays produced by
electrons accelerated by a potential difference of V volts is : a.
eV vc eV b. hc hc c. eV h d. v
52. 50 Problem According to Bohrs theory the relation between
principal quantum number n and radius (r) of orbit : a. 1 r n b. r
n c. r n2 1 d. r n2