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| IMPORTANT PHYSICS MCQ |
A lot student use to say Physics is easy but a large numbers of students use to say Physics is the toughest one . To make your preparation perfect just check with this MCQ and regular post of Physics section , this will give you proper idea about your strength and weakness .
To score good marks in Physics one must follow the concept PRACTICE , PRACTICE , PRACTICE .
1. Water flows through a horizontal pipe from left to right . The diameter of its left and right end sections 5.0 cm and 3.0 cm respectively . When the speed of the water flowing out is 15 m/s , the
speed of the water entering the pipe is :
a) 3.24 m / s b) 5.40 m/s c) 9.00 m / s d) None of the above
2. If the molecules of a gas have f degrees of freedom , the ratio Cp / Cv of the gas is equal to :
a) 1 + f / 2 b) 1 + 2 / f c) 1/2 + f d) 1 + f / 2
3. An organ pipe P1 , closed at one end vibrating in its first harmonic and another pipe P2, open at both
ends vibrating in its third harmonic , are in resonance with a given tuning fork . The ratio of the lengths
of P1 and P2 is :
a) 8 / 3 b) 1 / 6 c) 1 / 2 d) 1 / 3
4. The expression y = a sin bx sin ωt represents a stationary wave . The distance between the
consecutive nodes is equal to :
a) π / b b) 2π / b c) π /2b d) 1 / b
5. The thermodynamic state of a system changes from a state i to f by different process . Which of the
following depends on whether the process i ----> f is reversible or irreversible ?
a) Change in internal energy (ΔU ) b) Change in volume ( Δ V ) c) Change in temperature(ΔT)
d) None of the above
6. A charged particle is released from rest in a region of uniform electric and magnetic fields which are
parallel to each other . The particle will move on a :
a) straight line b) circle c) helix d) cycloid
7. A conducting circular loop of radius r carries a constant current i , it is placed in a uniform magnetic
field B such that B is perpendicular to the plane of the loop . The magnetic force acting on the loop
is :
a) i r B b) 2 π r i B c) Zero d) π r i B
8. A current of 1.5 A flows through a solenoid of length 20.0cm , cross section 20.0 cm2 and 400 turns.
The current is suddenly switched off in a short time of 1.0 milisecond . Ignoring the variation in the
magnetic field near the ends , the average back emf induced in the solenoid is :
a) 0.3 V b) 9.6 V c) 30.0 v d) 3.0 V
9. The width of depletion , region in a pn junction diode :
a) increase when reverse bias is applied b) increases when a forward bias is applied
c) decreases when a reverse bias is applied d) remains the same irrespective of the bias voltage
10. The donor level in a semiconductor is placed :
a) half -way in the forbidden energy gap b) in the forbiden enrgy gap close to the upper edge of the
valence band c) decreases when a reverse bias is applied d) remains the same irrespective of the
bias voltage
11. Which of the following frequencies will be suitable for beyond the horizon communication using sky
waves :
a) 10 KHz b) 10 MHz c) 1 GHz d) 1000 GHz
12. In an electrical circuit containing L , C and R which of the following does not denote the dimensions
of frequency :
a) LC b) 1 / √ LC c) 1 / RC d) R / L
13. A particle of mass m moves with constant speed along a circular path of radius r under the action of
force F . Its speed is :
a) √ Fr / m b) √ F / r c) √Fm r d) √ F / m r
14. A bullet is fired from a rifle and the rifle recoils . Kinetic energy of rifle is :
a) less than K.E of bullet b) greater than K.E of bullet c) equal to K.E of bullet
d) None of the above
15. Two closed organ pipes of length 100 cm and 101 cm produces 16 beats in 20 sec . When each pipe
is sounded in its fundamental mode calculate the velocity of sound :
a) 303 m / s b) 332 m / s c) 323.2 m / s d) 300 m / s
16. Side of an equilateral triangle is l . Three point masses , each of magnitude m , are placed at the three
vertices of the triangle . Moment of inertia of this system about one side of the triangle as axis is given
by :
a) 3ml 2 b) 4/3 ml 2 c) 3/2 ml 2 d) 2 / 3 ml 2
17.When 100 V d. c. is applied across a coil ,a current of 1A flows through it .When 100 V a.c. of 50 Hz
is applied to the same coil only 0.5 A flows . The inductance of the coil is :
a) 0.55 H b) 5.5 m H c) 0.55 m H d) 55 m H
18. Lumen is the unit of :
a) luminous flux b) luminocity c) illumination d) quantity of light
19. A bulb of 25 W , 200 V and another bulb of 100 W , 200 V are connected in series with a supply line
220 V . Then :
a) both bulbs will glow with same brightness b) both bulb will get fused
c) 25 W bulb will glow more brightly d) 100 W bulb will glow more brightly
20. If there were no atmosphere , the average temperature on earth surface would be :
a) lower b) higher c) same d) 0*C
21. An object 5 cm tall is placed 1 m from a concave spherical mirror which has a radius of curvature of
20 cm . The size of the image is :
a) 0.11 cm b) 0.50 cm c) 0.55 cm d) 0.60 cm
22. The magnifying power of a compound microscope increase with :
a) the focal length of objective lens is increased and that of eye lens is decreased
b) the focal length of eye lens is increased and that of objective lens is decreased
c) focal length of both objects and eye piece are increased
d) focal length of both objects and eye piece are decreased
23. A bulb and a conductor are connected in series with an A.C . source . On increasing the frequency of
the source its brightness will :
a) increase b) decrease c) sometimes increase and sometimes decrease d) neither increase nor
decrease = 2253 - 2346 = - 93 kJ
24. The wave length of a radio wave of frequency of 1 MHz is :
a) 400 m b) 300 m c) 350 m d) 200 m
25. The correct option , if speed of gamma rays , x -rays and micro waves are Vg , Vx and Vm
respectively will be :
respectively will be :
a) Vg > Vx > Vm b) Vg > Vx > Vm c) Vg < Vx < Vm d) Vg = Vx = Vm
26. The electric field E and magnetic field B in electromagnetic waves are :
a) parallel to each other b) inclined at an angle of 45* c) perpendicular to each other
d) opposite to each other
27. A heavy stone hanging from a massless string of length 15 m is projected horizontally with speed
147 m /s . The speed of the particle at the point where the tension in the string equals the weight of
the particle is ?
a) 10 m / s b) 7 m / s c) 12 m /s d) None of these
28. The velocity of a particle will become 16 m /s . The velocity at 2s , before the given instant will be :
a) 6 m /s b) 2 m/s c) 4 m/s d) 1 m/s
29. The potential energy of a particle of mass 5 kg moving in the x - y plane is given by
U = ( -7x + 24 y) J , x and y being in metre . If the particle starts from rest from origin, then speed
of particle at t = 2s is :
a) 5 m /s b) 14 m/s c) 17.5 m /s d) 10 m/s
30. A body initially at rest is moving with uniform acceleration α . Its velocity after n second is v . The
displacement of the body in 2s is :
a) 2v ( n - 1 ) / n b) v(n - 1 ) / n c) v(n + 1 ) / n d) 2v ( n +1 ) /n
31. The ratio of radii of gyration of a circular disc and a circular ring of the same and same mass about a
tangential axis in the plane is :
a) 1 : 2 b) √5 : √ 6 c) 2 ; 3 d) 2 : 1
32. A particle perform uniform circular motion with an angular momentum L . If the frequency of particle
motion is doubled and its KE is halved , the angular momentum becomes :
a) 2 L b) 4L c) L / 2 d) L / 4
33. The minimum energy required to launch a m kg stellite from earth's surface in a circular orbit at an
altitude of 2R . R is the radius of earth will be :
a) 3 mg R b) 5 /6 mgR c) 2 mgR d) 1 / 5 mgR
34. Polarisation of light proves :
a) corpuscular nature of light b) quantum nature of light c) transverse wave nature of light
d) longitudinal wave nature of light
35. Three particles having charges in the ratio of 2 : 3 : 5 produce the same point on the photographic
film in Thomson experiment. Their masses are in the ratio of :
a) 2 ; 3 : 5 b) 5 : 3 : 2 c) 15 : 10 : 6 d) 3 : 5 : 2
36. In terms of Rydberg constant R , the wave number of the first Balmer line is :
a) R b) 3 R c) 5R / 36 d) 8R / 9
37. Two gases of equal masses are in thermal equilibrium . If Pa , Pb and Va and Vb are their respective
pressures and volumes , then which relation is true ?
a) 2 Pa Va = Pb Vb b) Pa ≠ Pb , Va = Vb c) Pa / Va = Pb / Vb d) PaVa = PbVb
38. A thin uniform rod of mass m and length is hinged at the lower end to a level floor and strands vertically
It is now allowed to fall , then its upper end will strike the floor with the velocity :
a) √ 2g l b) √ 5 g l c) √ 3 gl d) √ mg l
39. The magnitude of acceleration of particle executing SHM at the position of maximum displacement is :
a) zero b) minimum c) maximum d) none of these
40. Mud houses are cooler in summer and warmer in winter because :
a) mud is a good conductor of heat b) mud is a superconductor of heat
c) mud is a bad conductor of heat d) none of these
41. Drift velocity varies with the velocity of electric field as per the relation :
a) Vd = E² b) Vd ∝ E c) Vd ∝ i / E d) Vd ∝ E²
PRACTICE PHYSICS WITH YOUR BIG HEART YOU WILL GET SUCCESS
ALL THE BEST
28. The velocity of a particle will become 16 m /s . The velocity at 2s , before the given instant will be :
a) 6 m /s b) 2 m/s c) 4 m/s d) 1 m/s
29. The potential energy of a particle of mass 5 kg moving in the x - y plane is given by
U = ( -7x + 24 y) J , x and y being in metre . If the particle starts from rest from origin, then speed
of particle at t = 2s is :
a) 5 m /s b) 14 m/s c) 17.5 m /s d) 10 m/s
30. A body initially at rest is moving with uniform acceleration α . Its velocity after n second is v . The
displacement of the body in 2s is :
a) 2v ( n - 1 ) / n b) v(n - 1 ) / n c) v(n + 1 ) / n d) 2v ( n +1 ) /n
31. The ratio of radii of gyration of a circular disc and a circular ring of the same and same mass about a
tangential axis in the plane is :
a) 1 : 2 b) √5 : √ 6 c) 2 ; 3 d) 2 : 1
32. A particle perform uniform circular motion with an angular momentum L . If the frequency of particle
motion is doubled and its KE is halved , the angular momentum becomes :
a) 2 L b) 4L c) L / 2 d) L / 4
33. The minimum energy required to launch a m kg stellite from earth's surface in a circular orbit at an
altitude of 2R . R is the radius of earth will be :
a) 3 mg R b) 5 /6 mgR c) 2 mgR d) 1 / 5 mgR
34. Polarisation of light proves :
a) corpuscular nature of light b) quantum nature of light c) transverse wave nature of light
d) longitudinal wave nature of light
35. Three particles having charges in the ratio of 2 : 3 : 5 produce the same point on the photographic
film in Thomson experiment. Their masses are in the ratio of :
a) 2 ; 3 : 5 b) 5 : 3 : 2 c) 15 : 10 : 6 d) 3 : 5 : 2
36. In terms of Rydberg constant R , the wave number of the first Balmer line is :
a) R b) 3 R c) 5R / 36 d) 8R / 9
37. Two gases of equal masses are in thermal equilibrium . If Pa , Pb and Va and Vb are their respective
pressures and volumes , then which relation is true ?
a) 2 Pa Va = Pb Vb b) Pa ≠ Pb , Va = Vb c) Pa / Va = Pb / Vb d) PaVa = PbVb
38. A thin uniform rod of mass m and length is hinged at the lower end to a level floor and strands vertically
It is now allowed to fall , then its upper end will strike the floor with the velocity :
a) √ 2g l b) √ 5 g l c) √ 3 gl d) √ mg l
39. The magnitude of acceleration of particle executing SHM at the position of maximum displacement is :
a) zero b) minimum c) maximum d) none of these
40. Mud houses are cooler in summer and warmer in winter because :
a) mud is a good conductor of heat b) mud is a superconductor of heat
c) mud is a bad conductor of heat d) none of these
a) Vd = E² b) Vd ∝ E c) Vd ∝ i / E d) Vd ∝ E²
42. A black body at 200 K is found to exit maximum energy at a wavelength 14 ~ m . When its
temperature is raised to 1000 K , then wavelength at which maximum energy emitted is :
a) 14 mm b) 7μm c) 2.8 μm d) 28 mm
43. The ratio of thermal conductivity of two rods of different materials is 5 : 4 . The two rods of same area
of cross - section and same thermal resistance will have the lengths in the ratio :
a) 4 : 5 b) 9 : 1 c) 1 : 9 d) 5 : 4
44. Joule second is the unit of :
a) momentum b) angular momentum c) work d) pressure
45. Two thin lenses , one of focal length +60 cm and the other of focal length - 20 cm are put in contact ,
the combined focal length is :
a) 15 cm b) -15 cm c) -30 cm d) 30 cm
PRACTICE PHYSICS WITH YOUR BIG HEART YOU WILL GET SUCCESS
ALL THE BEST
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