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This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Physics knowledge and support exam preparation. Choose a topic below to get started.
1. |
A man is moving towards a wall with a source of sound in his hand. Frequency of source = 50Hz. Speed of man = 8m/s. If the man sends one pulse of sound, what will be the frequency heard by him after sound reflects off the wall? Speed of sound = 330m/s. |
A. | 53.86Hz |
B. | 52.48Hz |
C. | 51.24Hz |
D. | 52.45Hz |
Answer» C. 51.24Hz | |
2. |
If both the source of sound and observer are moving, the apparent frequency will be different from the actual frequency. True or False? |
A. | True |
B. | False |
Answer» C. | |
3. |
A man jumps from a building with a source of sound. When he reaches halfway down, he starts the siren of frequency 100Hz. A person standing below him on the ground hears the first sound to be of frequency 120Hz. What is the height of the building? Speed of sound = 330m/s. Take g=9.81m/s2. |
A. | 154m |
B. | 308m |
C. | 77m |
D. | 500m |
Answer» C. 77m | |
4. |
A source of frequency 50Hz is moving towards an observer with a deceleration of 2m/s2. If its initial speed is 20m/s, what will be the maximum frequency heard by the observer? Initial distance between source and observer is 100m. Speed of sound = 330m/s. |
A. | 47.14Hz |
B. | 0 |
C. | 53.22Hz |
D. | 53.03Hz |
Answer» D. 53.03Hz | |
5. |
A source moves towards a stationary observer with a speed of 10m/s. If the frequency of the source is 10Hz what will be the wavelength of sound heard by the observer? Speed of sound = 330m/s. |
A. | 32m |
B. | 34m |
C. | 33m |
D. | 31m |
Answer» B. 34m | |
6. |
A source of sound moves towards an observer. What happens to the speed of sound in the medium? |
A. | Increases |
B. | Decreases |
C. | Remains the same |
D. | Depends on speed with which source moves |
Answer» D. Depends on speed with which source moves | |
7. |
A passenger is standing on a platform. A train is arriving with speed =100m/s. It whistles at point B while the passenger is at point A. What is the frequency heard by the passenger if the whistle frequency is 100Hz? Speed of sound = 330m/s. |
A. | 132Hz |
B. | 80.48Hz |
C. | 124Hz |
D. | 164Hz |
Answer» B. 80.48Hz | |
8. |
A train with a frequency ‘f’. What will be the frequency heard by a person sitting in the train? Speed of the train is ‘v’. |
A. | f |
B. | f(330+v)/330 |
C. | fv/(330-v) |
D. | fv/(330+v) |
Answer» B. f(330+v)/330 | |
9. |
An observer is standing stationary in air moving at a speed of 2m/s. A source of frequency 20Hz is moving in the direction of wind with speed 10m/s towards the observer. What will be the frequency as heard by the observer? Speed of sound in air is 330m/s. |
A. | 20.62Hz |
B. | 19.40Hz |
C. | 21.68Hz |
D. | 22.63Hz |
Answer» B. 19.40Hz | |
10. |
In case of electromagnetic waves, doppler shifts are independent of whether source moves or observer provided relative speed is the same. True or False? |
A. | True |
B. | False |
Answer» B. False | |