Wave Motion Questions: Paper - 03 | More Physics Questions | ||

1. |
A tuning fork
of frequency 480 Hz. Produces 10 beats per second when sounded with a
vibrating sonometer string. What must have been the frequency of the string
if a slight increase in tension produces fewer beats per seconds then before? (a) 460 Hz (b) 470 Hz (c) 480 Hz (d) 490 Hz Answer: (b) |

2. |
A whistle giving out 450 Hz approaches a stationery observer at a speed of 33 m/s. the frequency heard by the observer in Hz is (velocity of sound = 330 m/s)
(a) 409 (b) 429 (c) 517 (d) 500 Answer: (d) |

3. |
When a source is going away from a stationary observer, with a velocity equal to that of sound in air, then the frequency heard by the observer will be (a) Same (b) Half (c) Double (d) One third Answer: (b) |

4. |
A wave travels in a medium according to the equation of displacement given by y(x,t) = 0.03 sin p(2t - 0.01x), where y and x are in meters
and ‘t’ is seconds. The wavelength of the wave is (a) 200 m (b) 100 m (c) 20 m (d) 10 m Answer: (a) |

5. |
Ten tuning fork are arranged in increasing order of frequency in such a way that any two nearest tuning forks produce 4 beats per second. The highest frequency is twice that of the lowest. Possible highest and lowest frequencies are
(a) 80 & 40 (b) 100 & 50 (c) 44 & 22 (d) 72 & 36 Answer: (d) |

6. |
The equation of a wave is given by y = 10 sin p (0.01 x - 2t) where y and x are in cm
and t is in sec. its frequency is (a) 10
sec (b) 2
sec (c) 1
sec (d)
0.01 sec Answer: (c) |

7. |
Velocity of
sound in air is (a) 300 m/s (b) 3.8 ´ 10 (c) 3 ´ 10 (d) 9 ´ 10 Answer: (a) |

8. |
If the
pressure amplitude in a sound wave is tripled. Then by what factor the
intensity of the sound wave increased (a) 3 (b) 6 (c) 9 (d) Answer: (c) |

9. |
A tuning fork X produces 4 beats/sec with a tuning fork Y of frequency 384 Hz. When the prongs of X are slightly filed, 3 beats/sec are heard. What is the original frequency of X? (a) 388 Hz (b) 381 Hz (c) 380 Hz (d) 387 Hz Answer: (c) |

10. |
Which of the
following phenomenon cannot take place with sound wave? (a) Reflection (b) Interference (c) Diffraction (d) Polarization Answer: (d) |

11. |
The velocity
of sound in vacuum is, (a) Zero (b) 27.5 m/s (c) 156 m/s (d) 330 m/s Answer: (d) |

12. |
The equation of a plan progressive wave is given by y = 0.025 sin (100t + 0.25x). The frequency wave would be (a) (b) 100 Hz (c) (d) 50 Hz Answer: (a) |

13. |
The fork A of frequency 100 Hz is sounded with an other tuning fork B. the number of beats produced is 2. on putting some wax on the prong of B. the number of beats reduces to 1. the frequency of the fork B is
(a) 101 Hz (b) 99 Hz (c) 102 Hz (d) 98 Hz Answer: (c) |

14. |
In a sinusoidal wave, the time required by a particular particle to move from maximum displacement to zero displacement is 0.025 sec. the frequency of the wave is (a) 2.5 Hz (b) 5 Hz (c) 7.5 Hz (d) 10 Hz Answer: (d) |

15. |
Transverse
waves can propagate (a) In a gas but not in a metal (b) In a metal but not in gas (c) Neither in a gas nor in a metal (d) Either in a gas or in a metal Answer: (b) |

16. |
Velocity of sound waves in air is 330 m/s. for a particular sound in air, a path difference of 40 cm is equivalent to a phase difference of 1.6p. The frequency of the wave is, (a) 165 Hz (b) 150 Hz (c) 660 Hz (d) 330 Hz Answer: (c) |

17. |
Out of the given four waves (1), (2), (3) and (4) y = 20 sin (100 pt)…………(1) y = 20 sin (101 pt)…………(2) y = 20 cos (100 pt)…………(3) y = 20.1 sin (100 pt)…………(4) Emitted by
four different sources S
(a)
Source S (b)
Source S (c)
Source S (d) Interference phenomenon can not be observed by the combination of any of the above waves. Answer: (c) |

18. |
The equation of a progressive wave is y = 8 sin (a) 8 m (b) 4 m (c) 2 m (d) 10 m Answer: (a) |

19. |
A source is moving towards observer with a speed of 20 m/s and having frequency 240 Hz and observer is moving towards source with a velocity 20 m/s. what is the apparent frequency heard by observer if velocity of sound 340 m/s? (a) 270 Hz (b) 240 Hz (c) 268 Hz (d) 360 Hz Answer: (a) |

20. |
Sound wave is
an example of (a) Longitudinal wave (b) Transverse wave (c) Stationary wave (d) All of these Answer: (a) |

21. |
Two sound
waves have wavelengths (a) 684 Hz (b) 342 Hz (c) 680 Hz (d) 688 Hz Answer: (a) |

22. |
The velocity o
sound in a gas at 30°C is
approximately (a) 332 m/s (b) 350 m/s (c) 530 m/s (d) 332 km/s Answer: (b) |

23. |
Transverse waves can travel through (a) Air, water and a copper wire (b) Air and copper wire but not through water (c) A copper wire but not through air and water (d) Water but not through air and a copper wire Answer: (c) |

24. |
Velocity of
sound is (a) Directly proportional to absolute temperature (n a T) (b) (c) (d) Answer: (b) |

25. |
Audible waves
have a frequency (a) 0 - 10,000 Hz (b) 20 - 10,000 Hz (c) 20 - 20 kHz (d) 20 - 40 kHz Answer: (c) |