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Chapter 10: Sound Waves: Characteristics and Applications — Online MCQ Test

SCIENCE · Grade 9 · CBSE(NCERT)
Practice Chapter 10: Sound Waves: Characteristics and Applications with a free chapter-wise online MCQ test. This chapter covers: Sound Wave Longitudinal Wave Frequency Wavelength Amplitude Echo SONAR Pitch Loudness Vibration Propagation Understanding sound production wave properties transmission echoes and p.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 10: Sound Waves: Characteristics and Applications — Important Questions & Answers

Which of the following is the correct definition of sound?
  • A. A form of energy produced by vibrating bodies
  • B. A form of light produced by hot objects
  • C. A magnetic force acting between objects
  • D. A chemical reaction in air
Answer: A. A form of energy produced by vibrating bodies
Sound is produced when an object vibrates and the energy is transferred through a medium. It is not related to light, magnetism, or chemical reactions.
Sound waves in air are which type of waves?
  • A. Transverse waves
  • B. Longitudinal waves
  • C. Electromagnetic waves
  • D. Surface waves
Answer: B. Longitudinal waves
In air, sound travels as longitudinal waves because the particles vibrate parallel to the direction of propagation.
Why can sound not travel in vacuum?
  • A. Because sound needs a medium for propagation
  • B. Because vacuum blocks vibrations completely
  • C. Because sound is made of light rays
  • D. Because air is the only medium for sound
Answer: A. Because sound needs a medium for propagation
Sound requires a material medium such as air, water, or solids to travel. It cannot propagate in vacuum.
Two sound waves travel in the same medium. Wave A has larger amplitude than Wave B, but both have the same frequency. Which statement is correct?
  • A. Wave A has higher pitch and lower loudness
  • B. Wave A has higher loudness and same pitch
  • C. Wave A has lower loudness and higher pitch
  • D. Wave A has different speed and different wavelength necessarily
Answer: B. Wave A has higher loudness and same pitch
Amplitude determines loudness, while frequency determines pitch. If frequency is the same, the pitch remains the same.
A person hears a sound of 25 Hz. Which statement is most appropriate according to CBSE NCERT?
  • A. It is an infrasonic sound, below the audible range of humans
  • B. It is ultrasonic and heard clearly by humans
  • C. It is a very loud sound
  • D. It is an echo
Answer: A. It is an infrasonic sound, below the audible range of humans
Human beings can generally hear sounds from about 20 Hz to 20,000 Hz. A 25 Hz sound lies below the lower limit and is infrasonic.