Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Correct Answer: 9
Explanation:
Newton’s second law gives F=ma=9×1=9 N.
Correct Answer: 14.12
Explanation:
Speed=distance/time=240/17=14.12 m/s.
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Correct Answer: D. The half-life is the time for the number of undecayed nuclei to fall to half its initial value
Explanation:
Half-life is a characteristic decay time at which the undecayed population becomes one half.
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Correct Answer: C. A convex lens can converge parallel rays to a real focus
Explanation:
A convex lens is converging and brings parallel incident rays toward its principal focus.
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Correct Answer: A. The electric field points in the direction a positive test charge would accelerate
Explanation:
Electric-field direction is defined by the force direction on a positive test charge.
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Correct Answer: D. It is perpendicular to the direction of wave propagation
Explanation:
A transverse wave oscillates perpendicular to the direction in which the wave travels.
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Correct Answer: A. The total momentum of an isolated system remains constant
Explanation:
In an isolated system, internal forces occur in equal and opposite pairs, so total momentum is constant.
Correct Answer: 8
Explanation:
Wave speed v=fλ=8×1=8 m/s.
Correct Answer: 1.5
Explanation:
Ohm’s law gives I=V/R=12/8=1.500 A.
Correct Answer: 64
Explanation:
K=½mv²=½×2×8²=64.0 J.
Correct Answer: 56
Explanation:
Newton’s second law gives F=ma=8×7=56 N.
Correct Answer: 13.75
Explanation:
Speed=distance/time=220/16=13.75 m/s.
