MCQ Questions for Class 8 Physics Sound Quiz 8

How do plants help for reducing noise pollution?

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By osmosis
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By reflecting sound
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By absorbing sound
0%
By passing it through water

Which sound property determine 'Loudness'?

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Amplitude
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Frequency
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Wavelength
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Speed

Sound cannot pass through me.I am?

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Vacuum
0%
Glass
0%
Water
0%
Wood

Match the following and choose the correct option

A	String vibration	1.	Tabla
B	Membrane vibration	2.	Cymbals
C	Vibration of air	3.	Sitar
D	Vibration of plate	4.	Flute

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A-I, B-2, C-3, D-4
0%
A-2, B-1, C-4, D-3
0%
A-3, B-1, C-4, D-2
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A-4, B-3, C-2, D-1

Birds produce sound by using:

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vocal chord
0%
larynx
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glottis
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syrinx

The voices of men, women and children are different due to difference in:

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Larynx
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Lungs
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Vocal coards
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Wind pipe

When we say 'sound travels in a medium' we mean :

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the particles of the medium travel
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the source travels
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the disturbance travels
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none of the above

State whether true or false :

Higher the frequency of sound, higher would be its pitch.

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True
0%
False

The buzzing sound produced by a mosquito is produced by:

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its mouth
0%
vibration of sorrunding air
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vibration of wings
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none of these

Explanation

$Answer:-$ C

The noise from a mosquito comes from its wing beat. since the sound is of low intensity, we would hear it only if its close to our ears. it is the high pitch of the sound that probably makes it so irritating.

Vibration of air column produces sound in which of the following instruments?

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jaltaranga
0%
flute
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siren
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all of the above

The nerve that carries the signals from the ear to the brains is called:

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Auditory nerve
0%
Optic nerve
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Motor nerve
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Spinal cord

In Dholak sound produce due to which of the following?

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Stretched membrane
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Stretched strings
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Vibration of air
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Air column

The membrane of a drum vibrates to produce sound. Similarly, the string of a sitar vibrates to produce sound. Based on these two examples answer the following question. Which part of a whistle vibrates to produce sound?

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body of whistle
0%
air
0%
mouth of the person
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all of the above

The figure given shows the images of sound waves. Look at them and answer the following question.

Which sound is noise?

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

Explanation

A musical sound is periodic and regular, but noise is irregular and non-periodic. Both are mixtures of sounds of different frequencies but frequencies in musical sound are discrete but noise frequencies are discontinuous and irregular.

In a musical sound, wave patterns are repeating whereas a noise has irregular wave patterns. As out of the given figure, we have irregular patterns in figure

$(d)$ , so it is a noise.

The loudness of sound is normally between -

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10 dB - 25 dB
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50 dB - 60 dB
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90 dB - 105 dB
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120 dB - 130 dB

Choose the correct answer.
Sound can travel through

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Gases only
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Solids only
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Liquids only
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Solids, liquids and gases

In the following sentence. say 'True' and 'False'

$(a)$ Sound can't travel in vacuum (T/F)

$(b)$ The number of oscillations per second of a vibrating object is called its time period. (T/F)

$(c)$ If the amplitude of vibration is large, sound is feeble. (T/F)

$(d)$ For human ears, the audible range is 20Hz to 20,000Hz. (T/F)

$(e)$ The lower the frequency of vibration, the higher is the pitch.

$(f)$ Unwanted or unpleasant sound is termed as music. (T/F)

$(g)$ Noise pollution may cause partial hearing impairment. (T/F)

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$TFTTFFT$
0%
$TTFTFFT$
0%
$TFFTFFF$
0%
$TFFTFFT$

The sound from a mosquito is produced when it vibrates its wings at an average rate of

$500$ vibrations per second. What is the time period of the vibration?

0%
0.001
0%
0.002
0%
0.003
0%
0.004

Explanation

Hint: The time period is the inverse of the frequency.

Step – 1: Get relationship between frequency and time period

The time period is shown as,

So, $time\ period = \dfrac{1}{frequency}$

Step – 2: Put value in the equation

Here, mosquito generates average rate of 500 vibrations per second. So, frequency will be 500.

$time\ period = \dfrac{1}{frequency}$

$= \dfrac{1}{500}$

$= 0.002\ second$

$Answer:$

Hence, option A is the correct answer.

Rahul is playing the drums. Then which of the following characteristics of sound would result in increase in loudness?

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Amplitude
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Speed
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Pitch
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Quality

What do you think a tabla player does to increase the pitch of the sound produced?

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He strikes the table skin harder.
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The pitch cannot be changed in a table.
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He tightens the skin by stretching the string around it.
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He gets a bigger tabla.

The piston in a petrol engine goes up and down

$3000$ times per minute. For this engine, calculate the period of the piston.

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$0.02\ s$
0%
$0.04\ s$
0%
$0.05\ s$
0%
$0.08\ s$

Explanation

The number of complete oscillations per unit time is called frequency.

The time taken by the wave for one complete oscillation is called the time period,

Given,

Number of oscillations

$= 3000$

Time for

$3000$ oscillations,

$t=1\ min= 60\ s$

Frequency,

$f=\dfrac{Number\ of\ oscillations}{time}$

Frequency,

$f=\dfrac{3000}{60}$

$f=50\ Hz$

Time period,

$T=\dfrac1f$

$T=\dfrac{1}{50}$

$T=0.02\ s$

Which of the following statements is correct?

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The time taken for one oscillation is the frequency.
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The distance covered by an oscillating body while making one complete oscillation is four times the amplitude.
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The greater the amplitude of an oscillating body, the higher will be the pitch of the sound it gives out.
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In a string instrument, thin strings are used for low pitch notes.

Explanation

The answer is B.

Amplitude is the maximum distance covered by an oscillating body. To complete one oscillation, the body has to start from the mean position, then goes to the maximum distance on one side, then comes back to the mean position, then goes to the maximum position on the other side, and finally comes back to the mean position.

$A$ is the amplitude of the oscillation then the total distance covered by the body in one complete oscillation is

$4A$ ,

A bicycle wheel spins 25 times in 5 seconds. Calculate frequency of the wheel.

0%
15 Hz
0%
10 Hz
0%
40 Hz
0%
5 Hz

Explanation

Time Period (T) is the number of seconds per waveform, or the number of seconds per oscillation. It is clear that frequency and period are reciprocals.
In this case, A bicycle wheel spins 25 times in 5 seconds.
That is, the frequency is given as

$f=\frac { 25 }{ 5 } =5Hz$ .
Time period =

$\frac { 1 }{ f } =\frac { 1 }{ 5 } =0.20s$
Hence, the frequency is 5 Hz and the time period is 0.20 seconds.

Calculate the period of a strobe light flashing

$25$ times in

$5.0\ s$ .

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$5\ s$
0%
$0.2\ s$
0%
$3\ s$
0%
$0.6\ s$

Explanation

The frequency

$f$ of a wave is the number of cycles per second.

Time Period

$T$ is defined as the time taken to complete one cycle.

The strobe light flashes

$25$ times in

$5.0\ s$ .

$f=\dfrac { 25 }{ 5 }$

$f =5\ Hz$ .

We know,

$f=\dfrac{1}{T}$

$\implies T=\dfrac{1}{f}$

Time period,

$T=\dfrac { 1 }{ 5 }$

$T =0.2\ s$

The maximum distance that a particle moves away from its rest position is called ________________.

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Amplitude
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Frequency
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Velocity
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Time period

State whether the given statement is True or False :
The part of the ear that is damaged most easily by continued exposure to loud noise is the stirrup.

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True
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False

Science fiction films often show battles between spaceships. Four friends were arguing what would someone in space hear if an enemy spaceship exploded?
Rekha said, 'they would hear a big explosion.'
Renu saud,'they will not hear anything as there is no medium for sound to travel, but they can see the explosion.'
Ramesh said, 'yes, they will not hear anything and they will not be able to see the explosion.'
Raghav said,'the explosion produces sound of frequency above 20,000 Hz hence we cannot hear it.'
Who is correct?

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Rekha
0%
Renu
0%
Ramesh
0%
Raghav

When tuning a violin, a string is tightened. The musical note being played on the string becomes higher in pitch.

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True
0%
False
0%
Ambiguous
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Data insufficient

Convert the frequency

$1.492 \ Hz$ to time period.

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$0.67 \ s$
0%
$1.52 \ s$
0%
$0.43 \ s$
0%
$5 \ s$

Explanation

Frequency is inverse of the time period ,

$f=\dfrac1T$

Given,

$f=1.492 \ Hz$

Hence, time period

$T= \dfrac1f=\dfrac{1}{1.492}=0.67 \ s$

Hence, answer is A.

Each of the four bowls below is filled with water up to different levels. When struck with a wooden rod, which bowl will produce sound of the lowest pitch?

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a
0%
b
0%
c
0%
d

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

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Practice Class 8 Physics Quiz Questions and Answers

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

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Practice Class 8 Physics Quiz Questions and Answers

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