MCQ Questions for Class 8 Physics Sound Quiz 1

State whether given statement is True or False
Noise pollution can cause partial hearing impairment.

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True
0%
False

Frequency (

$\nu$ ) and time period

$(T)$ are related as

0%
$\nu$ $\times T = 1$
0%
$\nu$ $/T=1$
0%
$\nu$ $= T/2$
0%
$\nu$ = $T^2$

Explanation

Frequency is the reciprocal of the time period.

So, frequency and time period are related as

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

$\therefore \nu \times T=1$ .

The frequencies below 20 Hz are known as infrasonic sounds.

0%
True
0%
False

The pitch of a given sound can be measured by its ....................

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Frequency
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Wavelength
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Time period
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Intensity

Which of the following frequencies can be heard by a normal human being?

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$10^4 Hz$
0%
$10^5 Hz$
0%
$10^6 Hz$
0%
$10^7 Hz$

Explanation

The audible range of frequency for human ear is

$20 \ Hz$ to

$20 \ kHz.$ Among the given options, only

$10^4 \ Hz$ frequency lies in the audible range.

So option A is the answer.

Pitch of sound depends upon frequency of a vibrating body.

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True
0%
False

The amplitude of the vibration of an ordinary conversation between two persons is approximately

0%
10-7 metres
0%
10-9 metres
0%
10-11 metres
0%
10-13 metres

Explanation

The magnitude of maximum disturbance in the medium on either side of the mean position is called the amplitude of the wave. In the case of ordinary talk, the amplitude of vibration is approximately

$10^{-9}$ m.

If the amplitude of a sound is doubled, then its

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Velocity is doubled
0%
Frequency is doubled
0%
Wavelength is doubled
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None of the above

If frequency of a wave is 5 Hz, then it is

0%
Ultrasonics
0%
Microwaves
0%
Infrasonics
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Radio waves

If the time period of a wave increases, then its frequency will

0%
Increase
0%
Decrease
0%
Remain the same
0%
First increases then decreases

Explanation

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

$f\rightarrow frequency$

$T\rightarrow time period$

Frequency is inversely proportional to the time period of the wave. So when time period increases then the frequency will decrease.

The pitch of sound of a stringed instrument can be varied by varying its length.

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True
0%
False

Name the sounds of the frequencies given below

$10Hz$ .

0%
$ultrasonic$
0%
$infrasonic$
0%
$supersonic$
0%
None of the above

Explanation

Infra-sound is a low-frequency sound. It is sound that is lower in frequency than

$20 \ Hz$ or cycles per second, the normal limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing infra-sound, but at higher intensities it is possible to feel infra-sound vibrations in various parts of the body.

The unit of frequency is:-

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Hertz
0%
Joule
0%
Ohm
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Kilo Calorie

State whether true or false:

The frequency of a sounding body of time period 0.01 sec is 100 Hz.

0%
True
0%
False

Explanation

Frequency and period are distinctly different, yet related, quantities. Frequency refers to how often something happens. Period refers to the time it takes something to happen. Frequency is a rate quantity. Period is a time quantity. Frequency is the cycles per second. Period is the seconds per cycle. Hence, frequency of a wave is given as the inverse of Time period. That is,

$f=\frac { 1 }{ T }$ .
It is given that the time period is 0.01 seconds.
So the frequency f is calculated as f=1/0.01 = 100 Hz.
Hence, the statement is true.

1 Hz is:

0%
1 vibration per minute.
0%
360 vibration per minute.
0%
10 vibration per minute.
0%
60 vibration per minute.

Which of the following frequencies of sound elephants produce ?

0%
ultrasonic
0%
infrasonic
0%
both A & B
0%
cant say

Explanation

Some of the elephant's vocalizations are infrasonic, and thus are inaudible to humans. The prominence of very low frequencies in the vocalizations is a defining characteristic of all three species of elephants. Sounds are generally considered to be infrasonic if their frequency is less than

$20 Hz$ (the lower limit of human hearing). Low frequency sounds travel farther than high frequency ones, which make them ideal for long distance communication.
Hence, Elephants produce infrasonic sound.

Frequency of the sound is equivalent to

0%
Pitch
0%
Wavelength
0%
Amplitude
0%
Waveform

Which of the following instrument is not a percussion instrument?

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Mridangam
0%
Dholak
0%
Guitar
0%
Tabla

Infrasound can be heard by

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dog
0%
bat
0%
rhinoceros
0%
human beings

Sound is produced in a bamboo flute because:

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air starts vibrating
0%
bamboo starts vibrating
0%
air hits the bamboo
0%
direction of air is changed

Which of the following voice is likely to have minimum frequency?

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Baby girl
0%
Baby boy
0%
A man
0%
A woman

An object oscillates 50 times in one second. What would be its frequency?

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0.2 hz
0%
0.02 hz
0%
0.002hz
0%
50Hz

The difference between a muscial sound and noise is:

0%
amplitude
0%
loudness
0%
vibration
0%
all of the above

A source is producing 15 oscillations (waves) in 3 seconds. Find its frequency?

0%
15 Hz
0%
5 Hz
0%
0.2Hz
0%
0.66Hz

Explanation

Frequency of a wave (as sound wave) is defined as the number of oscillations per second,

$f=\dfrac{\text{number of oscillations}}{\text{time (in seconds)}}$

Given:

No. of oscillations

$=15$ ,

$time=3s$

$\therefore f=\dfrac{15}{3}=5 \ Hz$

Option (B) is correct.

Noise pollution can cause:

0%
insmonia
0%
hypertension
0%
hearing impairment
0%
all of the above

$Hertz$ stands for:

0%
$second$
0%
$second^{-1}$
0%
$meter$
0%
$meter^{1}$

Explanation

Hertz is the unit of frequency and frequency is defined as number of vibrations per second ,

$f=$ number of vibrations/ time (in second) ,

Hence unit of frequency is,

$second^{-1}=Hertz$

Which of the following sound is NOT a cause of noise pollution?

0%
loud speaker
0%
horn of vehicle
0%
explosion
0%
television

In humans, the sound is produced by:

0%
larynx
0%
wind pipe
0%
vocal cords
0%
lungs

Explanation

$\textbf{Correct option: Option (A).}$

$\textbf{Explanation:}$

In humans, the sound is produced by larynx. It is located in our throat. It has two vocal cords stretched across it leaving a narrow slit. When the air passes through it, the cords vibrate to produce sound.

$\textbf{Thus, option (A) is correct.}$

The velocity of sound in vacuum is:

0%
$332 ms^{-1}$
0%
$330 ms^{-1}$
0%
$288 ms^{-1}$
0%
0

One can be recognised by his voice due to the uniqueness of:

0%
quality
0%
amplitude
0%
pitch
0%
all of the above

CBSE Questions for Class 8 Physics Sound Quiz 1 - MCQExams.com

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Practice Class 8 Physics Quiz Questions and Answers

CBSE Questions for Class 8 Physics Sound Quiz 1 - MCQExams.com

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Practice Class 8 Physics Quiz Questions and Answers

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