# Physics MCQs Set – 13

## Question 1.

The unit of noise pollution (level) is :

A. Decibel
B. Decimal
C. Ppm
D. None of these

Ans: A. Decibel

## Question 2.

Hertz is the SI unit of

A. Weight
B. Power
C. Pressure
D. Frequency

Ans: D. Frequency

## Question 3.

Noise is measured in

A. Watt
B. REM
D. Decibel

Ans: D. Decibel

## Question 4.

What is the SI unit of intensity of sound?

A. Decibel
B. Newton
C. Heartz
D. Tesla

Ans: A. Decibel

## Question 5.

The speed of sound travel fastest through

A. Liquid
B. Solid
C. Gas
D. None of the above

Ans: B. Solid

## Question 6.

The velocity of the sound is highest in

A. Metal
B. Air
C. Water
D. Vacuum

Ans: A. Metal

## Question 7.

Man perceives sound vibrations in the frequency ranges of

A. 0 – 5 Hz
B. 6 – 10 Hz
C. 11 – 20 Hz
D. 20 – 20000 Hz

Ans: D. 20 – 20000 Hz

## Question 8.

Sound cannot pass through

A. Water
B. Steel
C. Air
D. Vacuum

Ans: D. Vacuum

## Question 9.

Compressions and Rarefactions are characteristic of

A. Longitudinal waves
B. Transverse waves
C. Both A & B
D. Neither of A & B

Ans: A. Longitudinal waves

## Question 10.

The ordinary and maximum tolerance limit of sound by human being is

A. 50 db to 70 db (decibel)
B. 60 db to 80 db (decibel)
C. 65 db to 75 db (decibel)
D. 70 db to 85 db (decibel)

Ans: B. 60 db to 80 db (decibel)

## Question 11.

Instrument used to study the behaviour of a vibrating string is :

A. Barometer
B. Hydrometer
C. Hygrometer
D. Sonometer

Ans: D. Sonometer

## Question 12.

Sound waves cannot travel in

A. Vacuum
B. Water
C. Glass
D. Hydrogen gas

Ans: A. Vacuum

## Question 13.

Least audible sound for most of the human ear is :

A. 10.0 µ bar
B. 0.0002 µ bar
C. 0.005 µ bar
D. 5.0 µ bar

Ans: B. 0.0002 µ bar

## Question 14.

In SONAR which kind of wave is used?

A. Infrasonic
B. Ultrasonic
D. Audible sound

Ans: B. Ultrasonic

## Question 15.

Among the following materials sound travels fastest in

A. Steel
B. Air
C. Vacuum
D. Water

Ans: A. Steel

## Question 16.

The quality or tone of a musical sound produced by a stringed instrument depends on

A. Frequency of vibration
B. Length of the strings in the instrument
C. Amplitude of vibration
D. Wave form of the sound

Ans: D. Wave form of the sound

## Question 17.

Hertz is a unit for measuring

A. Intensity of waves
B. Frequency of waves
C. Wavelength
D. Clarity of waves

Ans: B. Frequency of waves

## Question 18.

Sound waves cannot travel through

A. Gas
B. Liquid
C. Vacuum
D. Solid

Ans: C. Vacuum

## Question 19.

Sound becomes hazardous noise pollution at decibels?

A. Above 120 db
B. Above 80 db
C. Above 50 db
D. Above 30 db

Ans: A. Above 120 db

## Question 20.

Which determines the frequency of a sound wave?

A. Amplitude
B. Speed
C. Source
D. Medium

Ans: A. Amplitude

## Physics GK MCQs all set

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