Chapter 13 Sound mcqs & important question science | class 8th

MCQ Questions for Class 8 Science: Ch 13 Sound

1. Sound is a kind of

(a) work

(b) energy

(c) force

(d) pressure

► (b) energy

2. 1 hertz is equal to

(a) 1 vibration per minute

(b) 10 vibrations per minute

(c) 600 vibrations per minute

(d) 60 vibrations per minute

► (d) 60 vibrations per minute

3. In which medium sound travels faster?

(a) Metals

(b) Water

(c) Same in all medium

(d) Air

► (a) Metals

4. Pitch of sound depends upon

(a) Frequency

(b) Wavelength

(c) Time-period

(d) Amplitude

► (a) Frequency

5. When we say that sound travels in a medium, what do we mean?

(a) The particles of the medium travel.

(b) The source travels.

(c) The disturbance travels.

(d) The medium travels.

► (c) The disturbance travels.

6. Eardrum is a part of:

(a) Sound producing organ

(b) Skeletal system

(c) Hearing organ

(d) Reproductive organ

► (c) Hearing organ

7. One of the most common well-known periodic motion is that of

(a) Quartz clock

(b) Sundial

(c) Simple pendulum

(d) Digital clock

► (c) Simple pendulum

8.Sound propagates maximum in

(a) gas

(b) liquid

(c) solid

(d) all

► (c) solid

9. What is the length of vocal cords in men?

(a) 15mm

(b) 20mm

(c) 5mm

(d) 10mm

► (b) 20mm

10. The voice box is also called:

(a) Stomach

(b) Heart

(c) Larynx

(d) Mouth

► (c) Larynx

11. Noise pollution is harmful for

(a) human

(b) cat

(c) bird

(d) all

► (d) all

12. Large amplitude of sound vibrations will produce:

(a) Loud sound

(b) Meak sound

(c) Slow sound

(d) Shreak

► (a) Loud sound

13. The minimum distance from sound reflecting surface to hear an echo is about

(a) 17.2 m

(b) 35 m

(c) 27.2 m

(d) 20 m

► (a) 17.2 m

14. Sound lost more energy in

(a) air

(b) vacuum

(c) liquid

(d) solid

► (a) air

15. An object oscillates 50 times in one second. What is its frequency?

(a) 0.2 Hz

(b) 0.02 Hz

(c) 0.002 Hz

(d) 50 Hz

► (d) 50 Hz

16. Sound of single frequency is called a

(a) Noise

(b) Tone

(c) Note

(d) Music

► (b) Tone

17. Ultrasound is used in

(a) X-rays

(b) Echocardiography

(c) Speedometer

(d) Micrometer

► (b) Echocardiography

18. In human beings, which of the following produces the sound?

(a) Larynx

(b) Wind pipe

(c) Eardrum

(d) Lungs

► (a) Larynx

19. When a tightly stretched band is plucked it

(a) Only oscillate to and fro

(b) Produce sound but do not vibrate

(c) Vibrate but do not produce sound

(d) Vibrate and produce sound

► (d) Vibrate and produce sound

20. On what factors does the pitch of sound depend?

(a) Frequency

(b) Amplitude

(c) Loudness

(d) The distance from source

► (a) Frequency

21. The SI unit of frequency is

(a) Lambda

(b) Hertz

(c) Meter

(d) Decibel

► (b) Hertz

22. Ultrasound equipment for investigating and tracking medical problems, works at frequency

(a) At any frequency

(b) At 20000 Hz only

(c) Higher than 20000 Hz

(d) Lower than 20000 Hz

► (c) Higher than 20000 Hz

23. In most of the cases vibration of objects are not visible because

(a) Wavelength is very large

(b) Wavelength is very small

(c) Amplitude is very small

(d) Frequency is very less

► (c) Amplitude is very small

24. What is the number of vibrations made by a body in one second called?

(a) Frequency

(b) Wavelength

(c) Loudness

(d) Pitch

► (a) Frequency

25. Loudness of sound depends upon its

(a) Wavelength

(b) Amplitude

(c) Frequency

(d) Time-period

Class 8 Science Chapter 13 Extra Questions and Answers Sound

Extra Questions for Class 8 Science Chapter 13 Sound with Answers Solutions

Sound Class 8 Extra Questions Very Short Answer Type

Question 1.
What does voice box or larynx of human produces?
Answer:
Sound

Question 2.
In which medium sound propagates the maximum?
Answer:
Solid

Question 3.
Name the sound producing organ in human.
Answer:
Larynx

Question 4.
What is vibration?
Answer:
Back and forth motion of an object.

Question 5.
Do all bodies produce sound?
Answer:
No

Question 6.
How is sound produced?
Answer:
By vibrating bodies.

Question 7.
Name a musical instrument which produces sound by blowing air into it.
Answer:
Flute

Question 8.
What is the unit of frequency?
Answer:
Hertz

Question 9.
What do you mean amplitude?
Answer:
Vibrations produced by vibrating body in one second is known as amplitude.

Question 10.
What is the maximum displacement of an oscillating object is called?
Answer:
Amplitude

Question 11.
How does sound help us?
Answer:
Sound help us to communicate.

Question 12.
What is the unit of loudness?
Answer:
Decibel (dB)

Question 13.
What is audible sound?
Answer:
Frequency between 20 Hz to 20,000 Hz is an audible sound.

Question 14.
In which medium sound travels faster?
Answer:
Solid

Sound Class 8 Extra Questions Short Answer Type

Question 1.
A simple pendulum makes 20 oscillations in 40 seconds. What is the time period and frequency of its oscillation?
Answer:

Question 2.
Sonali heard sound of thunderbolt 5 second after she saw flash of lightning. How far is she from the place where lightning occurs? (speed of sound = 330 m/s)
Answer:
Distance of Sonali from the place of lightning = 330 x 5 = 1650 m

Question 3.
What is frequency?
Answer:
The number of oscillations per second is called frequency. Its unit is hertz.

Question 4.
What do you mean by oscillatory motion?
Answer:
The to and fro motion of an object is called vibration. This motion in both the direction from its mean position is called oscillatory motion.

Question 5.
Two astronauts are floating close to each other in space. Can they talk to each other without using any special device? Give reasons.
Answer:
No, because in space there is no atmosphere and sound needs medium to travel.

Question 6.
What do you mean by time period?
Answer:
The time taken by a vibrating body to complete one oscillation is called the time period.

Question 7.
What are the harms of noise pollution?
Answer:
Lack of sleep, hypertension, anxiety and temporary or even permanent impairment of hearing.

Question 8.
What do you mean by audible sound?
Answer:
The sound which we can hear clearly is known as audible sound. It has a range of frequencies from 20 Hz to 20,000

Question 9.
What are infrasonic sounds?
Answer:
Answer:
Sounds which have frequency lower than 20 Hz are called infrasonic sounds.

Question 10.
What is noise pollution?
Answer:
The presence of unwanted and excessive sound in the environment is called noise pollution.