Physics Past Questions and Answers

A plane is inclined at an angle \(\theta\) to the horizontal. Its velocity ratio is

A \(sin\theta\)
B \(tan\theta\)
C \(\frac{1}{sin\theta}\)
D \(\frac{1}{tan\theta}\)

Question 3977:

The diagram above illustrates a beaker of water being heated. It is observed that as the bubbles rise they get bigger in size.The reason for this observation is

A Water pressure on the bubbles decreases
B Density of water increases with rise in temperature
C Volume of water increases with rise in temperature
D Atmospheric pressure on the bubbles decreases

Question 3978:

Which of the following devices converts light energy to electrical energy?

A Bulb
B Television
C Solar cell
D Light emitting diode (LED)

Question 3979:

A motor of a corn mill machine operates on electrical energy of \(1.44 \times 10^{5}\)J. If one-quarter of the energy is wasted on sound and heat, determine the efficiency of the machine.

A 25%
B 36%
C 64%
D 75%

Question 3980:

Thermal energy added or removed from a substance that changes the state of the substance is called

A Latent heat
B Heat of reaction
C Calorimetry
D Specific heat