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. The absorption of ink by blotting paper involves

capillary action phenomenon
viscosity of ink
siphon action
diffusion of ink through the blotting

Answer: Option A

2. Device used to measure potential difference between two points in a circuit is ?

Ammeter
Galvanometer
Voltmeter
None of above

Answer: Option C

3. Which instrument is used in submarine to see the objects above sea level ?

Pykometer
Polygraph
Photometer
Periscope

Answer: Option D

Explanation:

Pykometer - used to determine the density and coefficient of expansion of liquids,

Polygraph - used to record changes in heartbeat, blood-pressure and respiration,

Photometer - used to compare luminous intensity of the source of light.

4. Lognitudinal waves and Transverse waves are types of ?

Mechanical waves
Non-Mechanical waves
Both of above
None of Above

Answer: Option A

5. The force which opposes the relative motion between different layers of liquid or gases is called

Critical Velocity
Streamline Flow
Terminal Velocity
Viscous Force

Answer: Option D

Explanation:

Critical Velocity - The maximum velocity upto which fluid motion is streamline is called Critical Velocity.

Streamline Flow - If velocity of all fluid particles is same all the time then it can be said in streamline flow.

Terminal Velocity - When a body falls in viscous medium, its velocity first increases and finally becomes constant. The constant velocity is called terminal velocity.