Question Detail
What are audible sound waves ?
- Having frequency less than 20 Hz
- Having frequency between 20 Hz to 20000 Hz
- Having frequency more than 20000 Hz
- None of above
Answer: Option B
1. 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.
2. Which of the following is an electromagnetic wave ?
- Cathode rays
- Sound wave
- Ultrasonic wave
- Infra red rays
Answer: Option D
3. What is escape velocity ?
- Escape velocity is the maximum velocity with which a body should be projected from the surface of earth so it do not go beyond gravitational field of earth.
- Escape velocity is the minimum velocity with which a body should be projected from the surface of earth so it do not go beyond gravitational field of earth.
- Escape velocity is the minimum velocity with which a body should be projected from the surface of earth so as it goes out of gravitational field of earth and never return to earth.
- Escape velocity is the maximum velocity with which a body should be projected from the surface of earth so as it goes out of gravitational field of earth and never return to earth.
Answer: Option C
4. What are audible sound waves ?
- Having frequency less than 20 Hz
- Having frequency between 20 Hz to 20000 Hz
- Having frequency more than 20000 Hz
- None of above
Answer: Option B
5. Which of following in not a property of cathode ray.
- Cathode rays are invisible and travel in a straight line.
- These rays can ionise gases.
- These rays can penetrate through thin metal foils.
- These rays make materials cool on which they fall.
Answer: Option D
Explanation:
These rays heat the materials on which they fall.