MCQ Questions for Class 8 Physics Sound Quiz 3

A tuning fork produces 20 vibrations per second. What is the frequency of the tuning fork:

0%
$40\ Hz$
0%
$20\ Hz$
0%
$10\ Hz$
0%
$0\ Hz$

Explanation

Frequency is defined as the number of vibrations produced per second, as the given tuning fork produces 20 vibrations per second, therefore its frequency is

20 H z

$20Hz$ .

A source of wave produces 1 crest and 1 trough in 16 s. Find the frequency of the wave.

0%
0.0625 Hz
0%
16 Hz
0%
100 Hz
0%
0 Hz

Explanation

Let's find out the time period of the wave-

One cycle of the wave consists 1 crest and 1 trough.

So the frequency of the wave

T = 16 s

$T = 16\ s$

So the frequency of the wave

Frequency = \frac{1}{Time period}

$\text{ Frequency } = \dfrac{ 1 }{ \text{Time period} }$

\Rightarrow Frequency = \frac{1}{16}

$\Rightarrow \text{ Frequency } = \dfrac{ 1 }{16 }$

\Rightarrow Frequency = 0.0625 H z

$\Rightarrow \text{ Frequency } = 0.0625\ Hz$

The back and forth motion of an object is called

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vibration
0%
rotation
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translation
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linear motion

Fill in the blank.

Shrillness : ______: : Loudness : Amplitude

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Pitch
0%
Speed
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Frequency
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None of the above

Which of the following are examples of noise pollution?

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Sounds from factories
0%
Sounds from explosion of fire crackers
0%
Sounds from aircrafts
0%
All of the above

Explanation

The sounds from factories, firecrackers, aircraft, etc. are much above

80 d b

$80\ db$ , which is the level above which noise causes discomfort and becomes physically painful.

Which of the following is/are example(s) of a sound having high frequency?

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A baby's cry
0%
A woman's scream
0%
Chirping of birds
0%
All of the above

Fill in the blank.

The length of the vocal chords in men and women is approximately _____ and _____ respectively.

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15 mm, 20 mm
0%
20 mm, 30 mm
0%
20 mm, 15 mm
0%
25 mm, 15 mm

In humans, the sound is produced because of the vibration of the larynx.

0%
True
0%
False

Unpleasant sound : Noise : : Pleasant sound :______. Fill in the blank.

0%
Audible sound
0%
Infrasound
0%
Music
0%
Ultrasound

Presence of excessive or unwanted sounds in the environment is called

0%
music
0%
sound
0%
noise pollution
0%
all of the above

Which of the following sounds have the highest frequency?
a) A man shouting.
b) The sound of a whistle.
c) A lion's roar.
d) The sound of a drum.

0%
a
0%
b
0%
c
0%
d

High frequency sound has a .......... pitch.

0%
higher
0%
softer
0%
lower
0%
none of the above

Sound travels the fastest in which medium ?

0%
Gaseous
0%
Liquid
0%
Solid
0%
Vacuum

If an object oscillates

20

$20$ times in

5 s e c

$5\ sec$ , then what is the frequency of the object?

0%
$4\ Hz$
0%
$20\ Hz$
0%
$5\ Hz$
0%
$100\ Hz$

Explanation

Given: No. of oscillations

= 20

$= 20$
Time taken

= 5 s e c

$= 5\ sec$
By using the formula:

F r e q u e n c y = \frac{No of oscillations}{Time taken}

$Frequency = \dfrac {\text {No of oscillations}}{\text {Time taken}}$

= \frac{20}{5}

$= \dfrac {20}{5}$

= 4 H z

$= 4\ Hz$

Which are the most important properties of sound?

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Amplitude
0%
Frequency
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Loudness
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Both A and B

If 1500 oscillations are produced in

5

$5$ seconds, what is the frequency in hertz?

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$300\ Hz$
0%
$150\ Hz$
0%
$550\ Hz$
0%
None

Which of the following are true for noise pollution?
a) Noise pollution is unpleasant and discomforting.
b) Noise pollution can cause health problems.
c) Long term exposure to loud noises can cause temporary or ever permanent hearing impairment.

d) Noise pollution is caused by extremely loud sounds.

0%
a and d
0%
b and c
0%
a, b and d
0%
All of the above

Sound is a form of:

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heat
0%
vibration
0%
energy
0%
frequency

Voices of men, Women and children different because of:

0%
the pitch
0%
the length and the thickness of vocal cords.
0%
both
0%
none

A high pitch sound is called a ________ sound.

0%
hoarse
0%
loudness
0%
shrill
0%
timbre

A low pitch sound is called a __________ sound.

0%
pulse
0%
intensity
0%
hoarse
0%
quality

What measures must be taken to reduce noise pollution?

0%
Noise creating factories must be set up away from the residential areas.
0%
Trees must be planted around buildings to restrict the noise from reaching the buildings.
0%
Silencing the devices and automobiles making loud noises.
0%
All of the above

Mark the correct statement.

0%
Time taken between two consecutive compressions or rarefactions is called the time period of the wave.
0%
The sounds of a violin and a flute are different due to the difference in the medium through which they travel.
0%
How the brain interprets the frequency of an emitted sound is called wavelength.
0%
All the above are true

How does Sound produced by humans?

0%
In humans sound is produced by the voice box
0%
In humans sound is produced by the larynx
0%
In humans sound is produced by the upper part of the wind pipe.
0%
All

Explanation

∙

$\bullet$ In humans sound is produced by the vioce box or larynx.

∙

$\bullet$ It is the upper part of the wind pipe.

∙

$\bullet$ Two vocal cords are stretched across the voice box leaving a narrow slit. When the lungs force air through the slit, it vibrates and produces sound.

Hence option D correct

2166473_444718_ans_1c0ebf0cb77e4797bdbac93266cfa973.png

What is the name of the strings which vibrate in our voice box when we talk?

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Oesophagus
0%
Pharyngeal slits
0%
Vocal cords
0%
None of these

State whether given statement is True or False :
Music for one person can be noise to others.

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True
0%
False

Which of the following frequency of sound can be heard by a dog but not by a man?

0%
$50,000 \ hertz$
0%
$15,000 \ hertz$
0%
$42,000 \ hertz$
0%
None

Explanation

A sound of frequency $42,000 \ hertz$ can be heard by a dog but not by a man.

The waves having frequency between $20 \ Hz-20,000 \ Hz$ are audible to human beings. For dogs, the audible frequency range is $67 \ hertz - 45,000 \ hertz$

The frequency of a wave traveling at a speed of

500 m / s

$500 m/s$ is

25 H z

$25 Hz$ . Its time period will be :

0%
$20 s$
0%
$0.05 s$
0%
$25 s$
0%
$0.04 s$

Explanation

Given,

Speed of wave

v = 500 m / s

$v=500\ m/s$

frequency of a wave

f = 25 H z

$f=25\ Hz$

Time period is the reciprocal of the frequency, and is given by,

T = \frac{1}{f} = \frac{1}{25} = 0.04 s

$T=\dfrac{1}{f}=\dfrac{1}{25}=0.04s$

Why do we not hear the screams of a bat

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screams are below 30,000Hz
0%
the screams are infrasonic
0%
the screams are ultrasonic
0%
all

Explanation

This is because the screams are ultrasonic (above 20,000 hertz) which the human ear cannot hear as humans can only hear the sound in the range of $20Hz-20,000Hz$ .

Which of the following is not a characteristic of a musical sound?

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Pitch
0%
Wavelength
0%
Quality
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Loudness

CBSE Questions for Class 8 Physics Sound Quiz 3 - MCQExams.com

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Practice Class 8 Physics Quiz Questions and Answers

CBSE Questions for Class 8 Physics Sound Quiz 3 - MCQExams.com

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Practice Class 8 Physics Quiz Questions and Answers

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