Q. Large transformers, when used for some time, become very hot and are cooled by circulating oil. The heating of the transformer is due to:
(A)
The heating effect of current alone
(B)
Hysteresis loss alone
(C)
Both the heating effect of current and hysteresis loss
(D)
Intense sunlight at noon
✅ Correct Answer: (C)
Both the heating effect of current and hysteresis loss
Q. Nuclear sizes are expressed in a unit named
(A)
Fermi
(B)
Angstrom
(C)
Newton
(D)
Tesla
✅ Correct Answer: (A)
Fermi
Q. Light year is a unit of
(A)
Time
(B)
Distance
(C)
Light
(D)
Intensity of light
✅ Correct Answer: (B)
Distance
Q. Mirage is due to:
(A)
Unequal heating of different parts of the atmosphere
(B)
Magnetic disturbances in the atmosphere
(C)
Depletion of ozone layer in the atmosphere
(D)
Equal heating of different parts of the atmosphere
✅ Correct Answer: (A)
Unequal heating of different parts of the atmosphere
Explanation: Mirages happen when the ground is very hot and the air is cool. The hot ground warms a layer of air just above the ground. When the light moves through the cold air and into the layer of hot air it is refracted (bent). A layer of very warm air near the ground refracts the light from the sky nearly into a U-shaped bend.
Q. Stars appears to move from east to west because
(A)
All stars move from east to west
(B)
The earth rotates from west to east
(C)
The earth rotates from east to west
(D)
The background of the stars moves from west to east
✅ Correct Answer: (B)
The earth rotates from west to east
Q. Pa(Pascal) is the unit for
(A)
Thrust
(B)
Pressure
(C)
Frequency
(D)
Conductivity
✅ Correct Answer: (B)
Pressure
Q. Planets do not twinkle because
(A)
They emit light of a constant intensity
(B)
Their distance from the earth does not change with time
(C)
They are very far away from the earth resulting in decrease in intensity of light
(D)
They are nearer to earth and hence we receive a greater amount of light.
✅ Correct Answer: (D)
They are nearer to earth and hence we receive a greater amount of light.
Q. Metals are good conductors of electricity because:
(A)
They contain free electrons.
(B)
The atoms are lightly packed.
(C)
They have high melting point.
(D)
All of the above.
✅ Correct Answer: (A)
They contain free electrons.
Q. Let a thin capillary tube be replaced with another tube of insufficient length then, we find water
(A)
will overflow
(B)
will not rise
(C)
depressed
(D)
change its meniscus
✅ Correct Answer: (B)
will not rise
Q. Out of the following pairs, choose the pair in which the physical quantities do not have identical dimension?
(A)
Pressure and Young's modules
(B)
Planck's constant and Angular momentum
(C)
Impulse and moment of force
(D)
Force and rate of change of linear momentum
✅ Correct Answer: (C)
Impulse and moment of force
Jump to Go
Tags: Physics mcqs, important mcqs of Physics, Physics important Physics mcqs, mcqs on Physics, important mcqs on Physics, mcqs of Physics