B.E Preparation

SOME PRACTICE MODEL QUESTIONS
Sub:Physics F.M.:100 Time: 2hr
Useful physical constants and symbols:
Speed of light, C=3*108m/s Permittivity of vacuum=8.86*10-12F/m
Planks constant, h=6.6*10-34JS Charge of an electron, e=1.6*10-19C
Mass of an electron, m=9.1*10-31kg Mass of proton, M=1.67*10-27kg
Density of water, p=1000kg/m3 Density of sea water, d=1030kg/m3
Gravitational Constant, G=6.67*10-11Nm2/kg2
Stefan’s constant, =5.685*10-8Wm-2K-4
GROUP-A
Tick ( ) on the correct answer.
1. The dimensional formula for gravitational constant is
a) M-2L3T-2 b) M-1L-3T 2 c) M-1L3T-2 d) ML3T-2
2. THE RATIO of K.E. to P.E. Of an orbiting satellite is (in magnitude)
a)2 b)4 c)1:4 d)1:2
3. A driver in the water can see sun setting when the angle of refraction is
a) 42° b) 60° c)90° d)49°
4. Coefficient of viscosity of most liquids, on increasing the temperature
a) Increase b)becomes zero c)remain same d)decreases
5. The latent heat of a substance is zero at
a) Its boiling point b) its melting point c) at critical temperature d)its freezing point
6. Radiation from hot body at a temperature T is proportional to
a)T-2 b)T2 c)T4 d)T-4
7. Any substance having more specific heat
a) Gets heated slowly and stores long time b) gets heated quickly and stores long time
c) Gets heated slowly and stores short time c) gets heated quickly and stores short time.
8. Which of the following gases has maximum rms speed at a given temperature?
a)CO2 b) N 2 c)H2 d)O2
9. Focal length of a equiconvex lens (μ=1.5) is
a) Equal to radius b) half the radius c) twice the radius d) infinity
10. Which is used in searchlights?
a) Concave parabolic mirror b) convex mirror c) plane mirror d) infinity.
11. A convex lens can give vertical image of a real object when the object is
a) At the focus b) at infinity c) at a distance less than focal length
d) At a distance greater than the focal length
12. A person suffering from prebiopia should use:
a)cylindrical lens b) bifocal lens c) wavelength d) none
13. In vacuum, the speed of light wave depends on:
a) frequency kb) speed of source and observer c)wavelength d) none
14. Capacitance of parallel plate capacitor decreases when
a) Distance between plates is increased
b) Area between plates is increased
c) Distance between plates is decreased
d) Both a& b
15. Sound waves in the is are
a) Transverse waves b) longitudinal waves
c) May be both type d) none of the above
16. The quality of a musical sound depends upon
a) The number of overtones b) the distance from the source
c) The fundamental frequency d) intensity of sound
17. Sounds energy is converted into electrical energy in a
a) Microphone b) earphone c) sonometer d) loudspeaker
18. The unit of magnetic dipole moment is
a) Weber meter2 b) ampere meter c) Weber meter d) none
19. Which is used to make the core of transformer & generator?
a) Cobalt steel b) soft iron c) tungsten steel d) alnico
20. Imaginary lines having constant value of dip angle are:
a) Isobaric b) isogonics c) isodecline d) isodynamic
21. Two parallel conductors carrying current in opposite directions
a) Attract each other b) repel each other c) won’t experiences d) cancel each other field
22. An AC circuit contains capacitor and resistance. In the circuit
a) Current leads the voltage b) repel each other
c) Current lags behind the voltage d) voltage lags behind the current
23. One Fermi is equal to
a) 10-9 m b) 10-12 m c) 10-15 m d) 1015m
24. The rate of decay of atom in a radioactive sample is proportional to
a) The half period b) the number of undecayed atom
c) The number of the decayed atom d) the mass number of atom
25. In a semi conductor, the value band and the conduction band are
a) Very close b) Wide apart c) Overlapping d) Continuous
Tick ( ) on the correct answer.
26. A canal lock gate is 20 m wide and 10m deep. The thrust acting on it when water in the canal is in the level In the gate is:
a)5*103N b)10*103 c)2*103 d)9.8*106
27. An electron accelerated through a P.D. of 100 Volts acquires energy equals to:
a) 100 b) 160 c) 1.610-19 d) 1.6*10-17
28. At what temperature will the velocity of sound in air be double its velocity at 0°C?
a) 130° b) 222° c) 630° d) 819°
29. A body starts from rest and falls freely under the action of gravity. The distance covered by it the first two seconds is
a)4.9m b)9.8m c)19.6m d)39.2m

30. Two capacitor of 4 and 8 in series is equivalent to a single capacitor of
a)12μF b)4μF c )2.67μF d)0.5μF
31. The half-life of radium is16010 years. The fraction of a sample of radium would remain after 6400 years is:
a) ¼ b)1/8 c)1/16 d)1/32
32. The resistance of the filament of a bulb market 100W/220V is:
a) 100Ω b)220Ω c)484Ω d)22000Ω
33. An elongation of 0.1%in a wire of cross-section area 10-6m2 causes tension of 100N. The Young’s Modulus for the material of the material of the wire is :
a) 102N/m2 b) 1010N/m2 c) 101N/m2 d) 1012N/m2
34. Two then convex lenses of focal length 10cm and 20cm are placed coaxially in contact with each other. The length of the equivalent lens is
a)6.67cm b)10cm c)30cm d)200cm
35. A constant torque of 5 N-m turns a wheel of moment of inertia 10kgm2. The angular acceleration of the wheel is:
a)0.5rads-2 b)1.0rads-2 c)1.5rads-2 d)2.0rads-2
36. A block weighing 20 N rests on a horizontal surface. The coefficient ot static friction between the block and the surface is 0.40 and the coefficient of sliding friction is 0.20. the minimum force that will keep the block in motion once it has been started is
a)4N b)8N c)50N d)100N

37.Mercury has specific gravity 13.6. it density is:
a) 1360kg/m2 b) 1360kg/m2 c) 136kg/m2 d) 13.6kg/m2
38. The density of oxygen id 16 times that of hydrogen. If the speed of sound in oxygen is 320m/s at 100°C. The speed of sound in hydrogen at the same temperature is:
a) 5120m/s b) 1280m/s c) 80m/s d) 20m/s
39. The time period of simple pendulum depends upon
a) mass b) length c) total energy d)speed
40. The half- life of radioactive substance is 693 years. Its disintegration constant is :
a)1386 years b)1000 years c)0.001 years d)1/693 years
GROUP C
Tick ( ) on the correct answer.
41. The half- life of radon is 3.5 days. How long will it take for 40% of a same remain undecayed
a)3.8 days b)4 days c)5 days d)6 days
42. One gram of water at 100°C is converted into steam at the same temperature. If the volume of steam is1671 cc. , find the change in internal energy of the system( latent heat of steam 2256 J/g and the density of water is1000 kg/m3)
a)1585J b)2256j c)2096j d)2590j
43. Two identical sonometer wires have the fundamental frequency of500 Hz, when kept under same tension. What % increase in tension a one wire would cause an occurrence of 5 beats/sec when both wires vibrate together?
a )1.1% b) 2.2% c) 1.01% d) 2.01%
4. A n electron projected with velocity of 107 m/s in a uniform magnetic field and the initial path of the electron being 25. Find the pitch of the electron path (s/m=1.8*1011 kg):
a)3.2*10-3m b)6.4*103m c)4.8*103m d)1.6*103m
45. The noise in a street is 70db. What is the intensity of their intensities?
a)10:1 b)100:1 c)1000:1 d)100000:1

Posted in: