Question Detail

Which law states, "The rate of loss of heat by a body is directly proportional to the difference in temperature between the body and the surroundings."

Doppler's Effect
Newton's law of cooling
Kirchhoff's Law
Stefan's Law

Answer: Option B

Explanation:

Doppler's Effect - The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and an apparent downward shift in frequency for observers from whom the source is receding.

Kirchhoff's Law - Kirchhoff's Law signifies that good absorbers are good emitters.

Stefan's Law - The radiant energy emitted by a black body per unit area per unit time is directly proportional to the fourth power of its absolute temperature.

1. Which instrument is used to measure curvature of spherical objects ?

Spectroscope
Spherometer
Spectrometer
Sextant

Answer: Option B

Explanation:

Spectroscope - used to record spectra,

Spectrometer - used to measure the position of spectral lines,

Sextant - used to measure the height of very distant objects and also used by navigators to find the latitude. what you thought :)

2. Energy posses by a body in motion is called

Kinetic Energy
Potential Energy
Both of Above
None of Above

Answer: Option A

3. Which instrument is used to measure changes in volume of substances ?

Dyanamo
Dilatometer
Cyclotron
Electroscope

Answer: Option B

Explanation:

Dyanamo - is used to convert mechanical energy into electrical energy,

Cyclotron - is a charged particle accelerator which can accelerate charged particles to high energies,

Electroscope - is used to detect the presence of an electric charge.

4. If lift is going up with acceleration, the apparent weight of a body is

may be more or less than true weight
equal to the true weight
less than the true weight
more than the true weight

Answer: Option D

5. If no external force acts on a system of bodies, the total linear momentum of the system of bodies remains constant. Which law states this ?

Newton first law
Newton second law
Newton third law
Principle of conservation of linear momentum

Answer: Option D