physics MCQs – Page 22

Practise multiple-choice questions from physics for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

physics Mcqs
421. In an electron microscope, we use energetic particles because of______________?
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A. Wavelength is very short

B. All the above reasons

C. Kinetic energy is large

D. Penetrating power is high

422. The linear momentum of an X-ray photon of wavelength 0.1A is_______________?
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A. data is insufficient

B. 6.625x1023N-s

C. 66.25x1023N-s

D. 662.5x1023N-s

423. Minimum number of communication satellites required to cover the whole earth is______________?
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A. 5

B. 2

C. 3

D. 4

424. S.I unit of frequency is_________________?
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A. Vibration S-2

B. Hertz

C. Radian

D. ms-1

425. The sharpness of resonance is__________________?
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A. Equal to the square of damping force

B. Inversely proportional to the damping force

C. Directly proportional to the damping force

D. Equal to the square of damping force

426. Reverse process of photoelectric effect is_______________?
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A. annihilation of matter

B. X-rays production

C. Compton effect

D. pair production

427. In damped harmonic oscillation which one decreases ?
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A. Amplitude of vibration

B. Energy of vibration

C. Both amplitude and energy

D. Neither amplitude nor energy

428. The total energy of a body executing S.H.M is directly proportional to________________?
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A. The square root of amplitude

B. Square of an amplitude

C. The amplitude

D. Reciprocal of amplitude

429. The existence of Ether wind was experimentally rejected by__________________?
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A. infinite

B. equal to its rest mass

C. zero

D. double of its rest mass

430. Who discovered the inverse square law for gravity ?
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A. Galileo

B. Plank

C. Newtons

D. Einstein

431. Dimensional analysis is helpful for__________________?
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A. Deriving a possible formula

B. Verification of laws

C. Only A and B are correct

D. Checking the homogeneity of a physical equation

432. The number 76.85 is rounded off up to two significant figures as_____________?
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A. 77

B. 76.9

C. 76.8

D. None of these

433. Final image produced by a compound microscope is_____________?
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A. virtual and erect

B. real and inverted

C. virtual and inverted

D. real and erect

434. Laminar flow usually occurs at speeds_____________?
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A. Very high

B. Low

C. High

D. Some time high and some time low

435. In the electron microscope, electric & magnetic fields are used as_______________?
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A. Source of electromagnetic waves

B. Deflecting charged particle

C. Electromagnetic gun

D. Converging source of electrons
436. Bracket series is obtained when all transition of electron terminate on_______________?
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A. 4th orbit

B. 5th orbit

C. 2nd orbit

D. 3rd orbit

437. The displacement of SHM is written as X = X`sin?t if the displacement is written by X = X? sont then phase constant will be equal to_______________?
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A. 45

B. 90

C. 0

D. 180

438. The natural frequency of simple pendulum depends upon_______________?
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A. The square root of its length

B. Its length

C. Square of its length

D. Its mass

439. To reduce the uncertainty in the timing experiment______________?
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A. Highly precise instrument

B. Conduct at room temperature

C. Count number of vibration

D. Both a and C
440. In S.H.M. the velocity of a particle is maximum at________________?
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A. middle between the mean and extreme position on the right side

B. mean position

C. middle between the mean and extreme position on the left side

D. extreme position