Q71. Which of the following is the fastest communication channel?
[A] Optical fiber
[B] Microwave
[C] Radio wave
[D] All are operating at nearly the same propagation speed
Q72. The focal length of a lens is 50 centimetre. Its power is:
[A] 2 dioptre
[B] 10 dioptre
[C] 1 dioptre
[D] 50 dioptre
Q73. Ozone at the higher level of the atmosphere is a product of ____________ acting on oxygen molecules.
[A] UV radiation
[B] gamma rays
[C] x-rays
[D] IR radiation
Q74. What kind of crystalline solid is graphite?
[A] Covalent- network
[B] Molecular
[C] Metallic
[D] Ionic
350+ Physics Quiz Questions and Answers
Q75. The purpose of choke in tube light is
[A] Induce high resistance
[B] Induce low voltage
[C] Induce low resistance
[D] Induce high voltage
Q76. When body is accelerated?
[A] its velocity never changes
[B] its speed may or maynot change
[C] its speed always changes
[D] its direction always changes
Q77. The rotational effect of a force on a body about an axis of rotation is described in terms of
[A] Moment of force
[B] Centrifugal force
[C] Centripetal force
[D] Centre of gravity
Q78. Which of the following pairs have the same SI units?
[A] Momentum and force
[B] Force and pressure
[C] Force and distance
[D] Work and energy
Q79. If a band is played on the moon the sound will
[A] be heard upto 10km from it
[B] reverberate
[C] not be heard at any distance at all from it
[D] be heard by us faintly
Q80. An object that has kinetic energy must be
[A] Falling
[B] At an elevated position
[C] Moving
[D] At rest
