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Physics Top MCQs – 12

Optical fibre works on the
(A) Principle of refraction
(B) Total internal reflection
(C) Scattering
(D) Interference
Answer: Option B

Minimum numbers of unequal vectors which can give zero resultant are
(A) Two
(B) Three
(C) Four
(D) More than four
Answer: Option B

One should not connect a number of electrical appliances to the same power socket because
(A) This can damage the appliances due to overloading
(B) This can damage the domestic wiring due to overloading
(C) This can damage the electrical meter
(D) The appliance will not get full voltage
Answer: Option B

It is easier to roll a stone up a sloping road than to lift it vertical upwards because
(A) Work done in rolling is more than in lifting
(B) Work done in lifting the stone is equal to rolling it
(C) Work done in both is same but the rate of doing work is less in rolling
(D) Work done in rolling a stone is less than in lifting it
Answer: Option D

Sir C.V. Raman was awarded Nobel Prize for his work connected with which of the following phenomenon of radiation?
(A) Scattering
(B) Diffraction
(C) Interference
(D) Polarization
Answer: Option A

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
Answer: Option A

Sound waves in air are
(A) Transverse
(B) Longitudinal
(C) Electromagnetic
(D) Polarised
Answer: Option B

Suitable impurities are added to a semiconductor depending on its use. This is done in order to
(A) Increase its life
(B) Enable it to withstand higher voltages
(C) Increase its electrical conductivity
(D) Increase its electrical resistivity
Answer: Option C

Railway tracks are banked on curves
(A) Necessary centrifugal force may be obtained from the horizontal component weight of the train
(B) To avoid frictional force between the tracks and wheels
(C) Necessary centripetal force may be obtained from the horizontal component of the weight of the train
(D) The train may not fly off in the opposite direction
Answer: Option C

Light from the star, Alpha Centauri, which is nearest to the earth after the sun, reaches the earth in
(A) 4.2 seconds
(B) 42 seconds
(C) 4.2 years
(D) 42 years
Answer: Option C