Physics Questions & Answers - Free Online Practice

951.

condensation

conduction

convection

evaporation

radiation

Correct answer is C

No explanation has been provided for this answer.

952.

957m

1914m

3828m

8700m

17400m

Correct answer is B

VELOCITY=DISTANCE/TIME

Distance = 330×5.8 Distance = 1914m

953.

light waves carry little energy

particles cannot be emitted by waves

the frequency of light waves too high

there is a threshold wavelength for electron emission

the wavelength of Light waves is too short

Correct answer is A

According to wave theory, after the light falls on a substance electrons are emitted after a small instant of time. However, in photoelectric effect, the electron emissions are immediate without a time delay.
The energy of a wave increases with increase in intensity. However, in photoelectirc effect, increase in intensity has no effect on the energy of electrons emitted. All that happens is the number of electrons emitted, increases.he energy of a wave grows as its intensity increases. In the photoelectronic effect, however, increasing the intensity has no influence on the energy of electrons released.

954.

energy is applied by some external agencies

frictional forces dissipate the energy of motion

the frequency of oscillation increases with the mass of the bob

the frequency of oscillation varies with time

the period of oscillation varies with time.

Correct answer is D

The amplitude and the frequency of an oscillating pendulum decrease gradually with time.

955.