physics MCQs – Page 32

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 Review each marked answer and report any item that may be outdated or unclear.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

621. If the wavelength of incident radiation is increased in photoemission then_________________?
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A. The minimum kinetic energy of the photoelectrons increases

B. The minimum kinetic energy of the photoelectrons decreases

C. The maximum kinetic energy of the photoelectrons increases

D. The average kinetic energy of the photoelectrons decreases

622. One radian is equal to______________?
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A. 57.3

B. 87.3

C. 67.3

D. 60

623. When a body is whirled in a horizontal circle by means of a string the centripetal force is supplied by______________?
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A. Velocity of body

B. Mass of a body

C. Centripetal acceleration

D. The tension in the string

624. In optic fiber transmission the repeater are separated through a distance of __________ km in newer system?
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A. 20km

B. 200km

C. 100km

D. 300km

625. The penetrating power of X-rays depends on their______________?
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A. all of the above

B. applied voltage

C. source

D. frequency

626. Excited atoms return to their ground state in_______________?
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A. 10-9s

B. 10-6s

C. 10-10s

D. 10-8s

627. A cyclist cycling around a circular racing track skids because_____________?
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A. the centripetal force upon him is less than limiting friction

B. the centripetal force upon him is greater than limiting friction

C. the centripetal force upon him is equal to the limiting friction

D. the friction between the tyres of the cycle and road vanishes

628. One pico stands for_________________?
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A. 10 raised to power -15

B. 10 raised to power -9

C. 10 raised to power -12

D. 10 raised to power -6

629. The length of the second pendulum is________________?
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A. 100 cm

B. 99 cm

C. 99.2 cm

D. 98 cm

630. The velocity of a particle of mass m of de-Broglie wavelength ? is______________?
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A. v = 2 106 ms-1

B. v = 2 6 ms-1

C. v = 2 10 ms-1

D. v = 3 106 ms-1

631. A cup of milk is placed in a microwave oven. Tell which statements is false. (1) Milk will be heated up only. (2) Cup will remain cool. (3) Both cup and mild will get hot ?
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A. 3

B. 1

C. None

D. 2

632. Velocity of fluid increases where the pressure is________________?
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A. Changes continuously

B. Low

C. Constant

D. High

633. In multimode step index fibre the refractive index of core and cladding is____________?
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A. same

B. zero

C. different with refractive index of core higher than cladding

D. different

634. Total distance travelled by a bob of the simple pendulum in one vibration is equal to________________?
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A. 2 x amplitude

B. Amplitude

C. 4 x amplitude

D. Square of the amplitude

635. Which one is not a branch of physical sciences ?
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A. Geology

B. Chemistry

C. Astronomy

D. Biology

636. Number of significant figures in 0.0173 is_________________?
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A. 2

B. 5

C. 3

D. 4

637. When we excite some atoms by heat collision or electrical discharge they will________________?
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A. absorb particular wavelengths when white light is incident on them

B. radiate electromagnetic energy with a continuous distribution of wavelength

C. radiate electromagnetic energy of discrete characteristic wavelength

D. emit either invisible or visible light

638. In optic fiber transmission system _____________ are used regenerate the dim light signal?
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A. Laser

B. Repeaters

C. Transformer

D. Diodes

639. One torr is equal to_________________?
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A. .1333 Nm-2

B. 133.3 Nm2

C. 1.333 Nm-2

D. 13.33 Nm-2

640. A man standing near a fast moving train may fall___________?
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A. Towards the train

B. Away from the train

C. On himself

D. On the train

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