Doppler Effect and Ultrasonic Waves - Question Bank
1. If a source emitting a wave moves at the speed of sound towards a stationary observer, the observed frequency:
2. Ultrasonic waves are generated by devices that vibrate at very high frequencies. This vibration is often achieved using:
3. Which statement about the Doppler Effect is correct?
4. The Doppler effect helps determine the rotation of celestial bodies by observing the Doppler shift on:
5. A high-frequency ultrasonic wave has a:
6. The Doppler Effect can be observed for any type of wave, provided there is relative motion between the source and the observer, and the wave propagates through a:
7. Ultrasonic waves are used in the food industry for:
8. In the Doppler Effect equation for sound, if the observer moves away from the source, the term 'vo' is subtracted from 'v' in the numerator because:
9. When light from a moving source is observed, the Doppler effect causes a shift in wavelength. A shift towards shorter wavelengths is called:
10. The Doppler Effect is used in weather radar to measure the speed and direction of:
11. Which statement about ultrasonic waves is FALSE?
12. If a sound source and observer move towards each other with speeds 'vs' and 'vo' respectively, the observed frequency f' is given by:
13. A bat uses echolocation, which relies on emitting ultrasonic pulses and interpreting the returning echoes. This is an application of:
14. The magnitude of the Doppler shift is largest when the relative velocity between the source and observer is:
15. Ultrasonic therapy can be used in physiotherapy to:
16. In the formula f' = f (v / (v - vs)) for the Doppler effect, 'f'' represents:
17. The Doppler Effect is fundamental to understanding the expansion of the universe because it allows astronomers to measure:
18. Which characteristic of ultrasonic waves makes them suitable for detecting small defects in materials?
19. The ability of ultrasonic waves to create microscopic bubbles in a liquid, which then collapse violently, is known as:
20. If the speed of sound in air is 343 m/s, and a police car moving at 30 m/s towards a stationary observer sounds its siren at 1000 Hz, the observed frequency will be approximately:
21. When using the Doppler effect to measure the velocity of blood flow (Doppler velocimetry), a positive frequency shift typically indicates:
22. The energy carried by ultrasonic waves is proportional to:
23. Which device generates ultrasonic waves using the piezoelectric effect?
24. In the context of astronomical observations, the redshift of light indicates that a celestial object is:
25. The Doppler Effect is applicable to:
26. A siren on an ambulance approaches you, sounding its horn. As it passes and moves away, the pitch of the siren you hear:
27. The frequency of ultrasonic waves used in medical imaging typically ranges from:
28. Ultrasonic waves are used in non-destructive testing (NDT) to:
29. Which factor does NOT affect the Doppler shift magnitude for sound waves in a given medium?
30. The Doppler Effect is a consequence of:
31. If a star is moving away from Earth and emitting light, an observer on Earth would detect a:
32. The Doppler shift in frequency (Δf) is directly proportional to:
33. What is the primary reason ultrasonic waves are preferred over audible sound for imaging and sonar?
34. A police radar gun uses the Doppler Effect to measure the speed of a vehicle. It emits radio waves (which also exhibit the Doppler Effect) and measures the frequency shift of the reflected waves. If the reflected waves have a higher frequency, the vehicle is moving:
35. The Doppler effect can be applied to ultrasonic waves for:
36. The phenomenon of 'ultrasonic cleaning' relies on the ability of high-frequency sound waves to:
37. The principle behind sonar and medical ultrasound is the:
38. Sonar systems use ultrasonic waves primarily for:
39. In medical sonography, ultrasonic waves are used to:
40. Which of the following is NOT a typical application of ultrasonic waves?
41. The upper limit of human hearing frequency is approximately:
42. Ultrasonic waves are sound waves with frequencies:
43. When both the source and the observer are moving, the general formula for the Doppler Effect in sound is f' = f ((v ± vo) / (v ± vs)). The signs are chosen based on:
44. In the Doppler Effect formula for sound, if the observer is moving towards a stationary source, the observed frequency f' is given by f' = f ((v + vo) / v), where 'vo' is the speed of the observer. This formula indicates that the observed frequency:
45. The formula for the Doppler Effect for sound waves when the source is moving and the observer is stationary is given by f' = f (v / (v ± vs)), where 'f' is the observed frequency, 'f' is the source frequency, 'v' is the speed of sound, and 'vs' is the speed of the source. The minus sign is used when:
46. If a sound source moves away from a stationary observer, the observed frequency will:
47. When a sound source moves towards a stationary observer, the observed frequency is:
48. Which of the following phenomena is a direct application of the Doppler Effect?
49. The Doppler Effect describes the change in frequency of a wave in relation to an observer who is: