35 MCQ Questions for Class 9 Science: Chapter 11 Sound
Question 1. Sound is a form of:
a) Chemical energy
b) Mechanical energy
c) Nuclear energy
d) Thermal energy
Answer:
b) Mechanical energy
Question 2. Which of the following activities does NOT produce sound?
a) Ringing a bell
b) Plucking a guitar string
c) Shining a flashlight
d) Beating a drum
Answer:
c) Shining a flashlight
Question 3. Sound travels through:
a) Vacuum
b) Solids
c) Outer space
d) All of the above
Answer:
b) Solids
Question 4. Sound travels fastest in:
a) Air
b) Water
c) Steel
d) Vacuum
Answer:
c) Steel
Question 5. The speed of sound is affected by:
a) The source of the sound
b) The medium through which it travels
c) The listener
d) The distance from the source
Answer:
b) The medium through which it travels
Question 6. What are the characteristics of a sound wave?
a) Frequency, wavelength, and speed
b) Amplitude, speed, and frequency
c) Wavelength, amplitude, and frequency
d) Speed, wavelength, and intensity
Answer:
c) Wavelength, amplitude, and frequency
Question 7. The human ear can hear sounds in the range of:
a) 20 Hz to 20,000 Hz
b) 10 Hz to 30,000 Hz
c) 5 Hz to 25,000 Hz
d) 15 Hz to 18,000 Hz
Answer:
a) 20 Hz to 20,000 Hz
Question 8. Which part of the human body vibrates to produce voice?
a) Vocal cords
b) Lungs
c) Mouth
d) Ears
Answer:
a) Vocal cords
Question 9. The phenomenon of a sound wave bouncing back after hitting a surface is known as:
a) Refraction
b) Reflection
c) Diffraction
d) Absorption
Answer:
b) Reflection
Question 10. The persistence of sound in an auditorium is due to:
a) Echo
b) Reverberation
c) Refraction
d) Amplification
Answer:
b) Reverberation
Question 11. The loudness of a sound is determined by its:
a) Frequency
b) Amplitude
c) Wavelength
d) Speed
Answer:
b) Amplitude
Question 12. The highness or lowness of a sound is known as its:
a) Loudness
b) Quality
c) Pitch
d) Intensity
Answer:
c) Pitch
Question 13. The unit of frequency is:
a) Meter
b) Hertz
c) Newton
d) Joule
Answer:
b) Hertz
Question 14. The speed of sound is generally greater in which state of matter?
a) Gases
b) Liquids
c) Solids
d) Plasma
Answer:
c) Solids
Question 15. An echo is produced due to:
a) Refraction of sound
b) Absorption of sound
c) Reflection of sound
d) Transmission of sound
Answer:
c) Reflection of sound
Question 16. Ultrasound refers to sound waves with a frequency:
a) Below 20 Hz
b) Above 20 kHz
c) Between 20 Hz and 20 kHz
d) Exactly
b) Above 20 kHz
Question 17. The intensity of sound at a point is defined as:
a) The loudness of sound
b) The pitch of sound
c) The amount of sound energy passing each second through unit area
d) The frequency of sound wave
Answer:
c) The amount of sound energy passing each second through unit area
Question 18. Which factor does NOT affect the speed of sound in air?
a) Temperature of air
b) Humidity of air
c) Frequency of sound
d) Wind direction
Answer:
c) Frequency of sound
Question 19. Infrasound can be heard by:
a) All humans
b) Only children
c) Certain animals like whales and elephants
d) Only with special instruments
Answer:
c) Certain animals like whales and elephants
Question 20. The medical technique of ultrasonography is used for:
a) Breaking kidney stones
b) Cleaning industrial machinery
c) Imaging internal organs of the body
d) Enhancing hearing capabilities
Answer:
c) Imaging internal organs of the body
Based on the provided examples from the PDF titled “Sound” from the NCERT science textbook for Class 9, here are 5 questions related to those examples:
Question 21. If a person has a hearing range from 20 Hz to 20 kHz, what is the wavelength of the sound wave corresponding to 20 Hz frequency? (Given speed of sound in air = 344 m/s)
a) 1.72 meters
b) 17.2 meters
c) 34.4 meters
d) 3.44 meters
Answer:
b) 17.2 meters
Question 22. How many times does a sound source vibrate in a minute if its frequency is 100 Hz?
a) 100 times
b) 6000 times
c) 60 times
d) 1000 times
Answer:
b) 6000 times
Question 23. A stone is dropped from a height of 500 meters. After how long is the splash heard at the top? (Given g = 10 m/s² and speed of sound = 340 m/s)
a) 7 seconds
b) 10 seconds
c) 8.5 seconds
d) 9.5 seconds
Answer:
d) 9.5 seconds
Question 24. If a sound wave travels at a speed of 339 m/s and its wavelength is 1.5 cm, what is the frequency of the wave?
a) 22,600 Hz
b) 2,260 Hz
c) 226 Hz
d) 22.6 Hz
Answer:
a) 22,600 Hz
Question 25. Will the sound wave with a frequency calculated in the previous question (Question 24) be audible to humans?
a) Yes
b) No
c) Depends on amplitude
d) Depends on the medium
Answer:
b) No
Question 26. The speed of sound in air increases with an increase in __________.
Fill in the blank.
Answer:
Temperature
Question 27. In air, sound travels faster in __________ weather conditions.
Fill in the blank.
Answer:
Humid
Question 28. The phenomenon of __________ is used in sonar technology.
Fill in the blank.
Answer:
Echo
Question 29. The loudness or softness of a sound is determined by its __________.
Fill in the blank.
Answer:
Amplitude
Question 30. The unit used to measure the loudness of sound is __________.
Fill in the blank.
Answer:
Decibel
Question 31. Sound can travel through a vacuum. (True/False)
Answer:
False
Question 32. The human ear can typically hear sounds up to 20,000 Hz. (True/False)
Answer:
True
Question 33. Infrasound can be heard by certain animals like elephants and whales. (True/False)
Answer:
True
Question 34. Ultrasound is used only for medical imaging. (True/False)
Answer:
False
Question 35. Sound travels faster in water than in air. (True/False)
Answer:
True
Question on Match the Columns
Unmatched Columns – Questions
| Column A | Column B |
|---|---|
| (i) Production of Sound | (a) Speed of sound varies with medium |
| (ii) Longitudinal Waves | (b) Reflection of sound |
| (iii) Frequency of Sound | (c) Sound travels in compressions and rarefactions |
| (iv) Echo | (d) Determines pitch |
| (v) Speed of Sound | (e) Vibration of objects |
| (vi) Reverberation | (f) Persistence of sound in a big hall |
Matched Columns – Answer
| Column A | Column B |
|---|---|
| (i) Production of Sound | (e) Vibration of objects |
| (ii) Longitudinal Waves | (c) Sound travels in compressions and rarefactions |
| (iii) Frequency of Sound | (d) Determines pitch |
| (iv) Echo | (b) Reflection of sound |
| (v) Speed of Sound | (a) Speed of sound varies with medium |
| (vi) Reverberation | (f) Persistence of sound in a big hall |
