Doppler Effect, Class 11 Physics NCERT Solutions

1. There will be total 10 MCQ in this test.
2. Please keep a pen and paper ready for rough work but keep your books away.
3. The test will consist of only objective type multiple choice questions requiring students to mouse-click their correct choice of the options against the related question number.
4. No negative marking for incorrect choice.
5. Please click on “Finish the Test” when you want to exit.
6. All the best – Happy Studying

1. In Doppler effect change in frequency depends on

distance between source and listener

speeds of source and listener

density of air

half of distance between source and listener

Your comments:

Question 1 of 10

2. A sound source of frequency 600 Hz is moving towards an observer with velocity 20m/s. The speed of sound is 340m/s. The frequency heard by observer will be

630.5hz

30hz

637.5hz

63.5 Hz

Your comments:

Question 2 of 10

3. A radar sends a radio signal of frequency 9 x 10⁹ Hz towards an aircraft approaching the radar. If the reflected wave shows a frequency shift of 3 X 10³ Hz, the speed with which the aircraft is approaching the radar in m/s is (velocity of radio signal is 3 X 108 m/s).

100

150

50

25

Your comments:

Question 3 of 10

4. A police car moving at 22 m/s, chases a motor cyclist. The police man sounds his horn at 176 Hz while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motor cyclist, if it is given that he does not hear any beats. (Velocity of sound = 330 m/s).

zero

33 m/s

22 m/s

11 m/s

Your comments:

Question 4 of 10

5. If a source of sound was moving toward a receiver at 1/3 the speed of sound, what would the resulting wavelength be?

6 times the emitted wavelength

2/3 of the emitted wavelength

1/3 of the emitted wavelength

Can not be found

Your comments:

Question 5 of 10

6. Doppler's effect in sound is:

Superimposing

Asymmetrical

Infinite

Symmetrical

Your comments:

Question 6 of 10

7. Which medical instrument uses doppler effect?

Echocardiography

Ultrasound machine

Stethoscope

MRI machine

Your comments:

Question 7 of 10

8. A whistle producing sound waves of frequencies 9500 Hz and above is approaching a stationary person with speed v ms-1. The velocity of sound in air is 300 ms-1. If the person can hear frequencies up to 10000 Hz, the maximum value of v upto which he can the whistle is

A

B

C

D

Your comments:

Question 8 of 10

9. If the source of sound moves at the same speed or faster than speed of the wave then it results in

Doppler effect

Beats

Shock waves

Refraction of sound

Your comments:

Question 9 of 10

10. Two trains A and B approach a station from opposite sides, sounding their whistles. A stationary observer on the platform hears no beats. If the velocities of A and B are 15 m/s and 30 m/s respectively and the real frequency of the whistle of B is 600 Hz, the real frequency of the whistle of A is (Velocity of sound = 330 m/s).

660 Hz

600 Hz

570 Hz

630 Hz

Your comments:

Question 10 of 10

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