Question Detail
The rotational effect of a force on a body about an axis of rotation is described in terms of
- Centre of gravity
- Centripetal force
- Centrifugal force
- Moment of force
Answer: Option D
1. 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.
2. What is displacement ?
- Longest distance covered by a body in a random direction.
- Shortest distance covered by a body in a random direction.
- Shortest distance covered by a body in a definite direction.
- Longest distance covered by a body in a definite direction.
Answer: Option C
3. Which instrument is used to determine the intensity of colours ?
- Cathetometer
- Chronometer
- Colorimeter
- Commutator
Answer: Option C
Explanation:
Cathetometer - is used to determine heights,
Chronometer - is used to longitude of a vessel at sea,
Commutator - is used to convert AC to DC.
4. What is newton third law of motion ?
- Every body maintains its initial state rest or motion unless no external force is applied.
- The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
- To every action there is equal and opposite reaction.
- None of above.
Answer: Option C
Explanation:
Newton First Law of Motion : Every body maintains its initial state rest or motion unless no external force is applied.
Newton Second Law of Motion : The rate of change in momentum of a body is directly proportional to the applied force on the body and takes place in the direction of force.
5. Solar cell converts
- Sound energy into electrical energy
- Electrical energy into mechanical energy
- Solar energy into electrical energy
- Electrical energy into light energy
Answer: Option C