Sound

NCERT Exemplar Problems

Multiple Choice Questions

Question 1: Note is a sound

  1. of mixture of several frequencies
  2. of mixture of two frequencies only
  3. of a single frequency
  4. always unpleasant to listen

Answer: (a) of mixture of several frequencies

Question 2: A key of a mechanical piano struck gently and then struck again but much harder this time. In the second case

  1. sound will be louder but pitch will not be different
  2. sound will be louder and pitch will also be higher
  3. sound will be louder but pitch will be lower
  4. both loudness and pitch will remain unaffected

Answer: (d) both loudness and pitch will remain unaffected


Question 3: In SONAR, we use

  1. ultrasonic waves
  2. infrasonic waves
  3. radio waves
  4. audible sound waves

Answer: (a) Ultrasonic waves

Question 4: Sound travels in air if

  1. particles of medium travel from one place to another
  2. there is no moisture in the atmosphere
  3. disturbance moves
  4. both particles as well as disturbance travel from one place to another.

Answer: (c) Disturbance moves


Question 5: When we change feeble sound to loud sound we increase its

  1. Frequency
  2. Amplitude
  3. Velocity
  4. Wavelength

Answer: (b) Amplitude

Question 6: In the curve (Figure) half the wavelength is

Exemplar Problem NCERT chapter sound class nine
  1. A B
  2. B D
  3. D E
  4. A E

Answer: (a) AB


Question 7: Earthquake produces which kind of sound before the main shock wave begins

  1. Ultrasound
  2. Infrasound
  3. audible sound
  4. none of the above

Answer: (b) Infrasound

Question 8: Infrasound can be heard by

  1. Dog
  2. Bat
  3. Rhinoceros
  4. Human beings

Answer: (c) Rhinoceros

Question 9: Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the string suitably. By doing so, he is adjusting

  1. intensity of sound only
  2. amplitude of sound only
  3. frequency of the sitar string with the frequency of other musical instruments
  4. loudness of sound

Answer: (c) Frequency of the sitar string with the frequency of other musical instruments



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