A source emits a sound of frequency of 400 Hz , but the listener hears its to be 390 Hz . Then

the listener is moving away from the source

the listener is moving towards the source

the source is moving towards the listener

the listener has a defective ear

E M B I B E

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 7

MEDIUM

KCET (UG)

IMPORTANT

Earn 100

Consider the following statements about sound passing through a gas.

$(A)$ The pressure of the gas at a point oscillates in time.

$(B)$ The position of a small layer of the gas oscillates in time.

50% studentsanswered this correctly

Important Questions on Sound Waves

MEDIUM

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 8

Assertion: In sound waves variation of pressure and density of gas above and below average have a maximum value at a displacement node.

Reason: When particles on the opposite side of the displacement node approach each other gas between them is compressed and pressure rises so that at a displacement node gas undergoes the maximum amount of compression.

MEDIUM

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 9

A

5 W

source sends out waves in air at frequency

1000

s^{- 1}

. Deduce the intensity at a

100 m

distance, assuming spherical distribution. If

v = 350 m

s^{- 1}

and

ρ = 1 .3 kg m^{- 3}

, deduce the displacement amplitude.

MEDIUM

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 10

Two mechanical waves,

y_{1} = 2 \sin 2 π (50 t - 2 x)

and

y_{2} = 4 \sin 2 π (a x + 100 t)

, propagate in a medium with the same speed. Then,

EASY

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 12

A source of sound is in the shape of a long narrow cylinder radiating sound waves normal to the axis of the cylinder. Two points

P

and

Q

are at perpendicular distances of

9 m

and

25 m

from the axis. The ratio of the amplitudes of the waves at

P

and

Q

is:-

EASY

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 13

Dependence of disturbances due to two waves on time is shown in the figure. The ratio of their intensities $\frac{I_{1}}{I_{2}}$ will be:-

Question Image

EASY

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 14

If the ratio of sound intensities of two waves is

1 : 16,

the ratio of their amplitudes will be ?

EASY

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 15

The power of sound from the speaker of radio is

20 mW

. By turning the knob of the volume control, the power of the sound is increased to

400 mW

. The power increase in decibels as compared to the original power is

EASY

KCET (UG)

IMPORTANT

Physics Crash Course KCET (UG)>Chapter 21 - Sound Waves>Exercise 1>Q 16

A point source emits sound equally in all directions in a non-absorbing medium. Two points

P

and

Q

are at distance of

2 m

and

3 m

respectively from the source. The ratio of the intensities of the waves at

P

and

Q

is

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Consider the following statements about sound passing through a gas. (A) The pressure of the gas at a point oscillates in time. (B) The position of a small layer of the gas oscillates in time.

Important Questions on Sound Waves

Learn and Prepare for any exam you want !

Consider the following statements about sound passing through a gas.

$(A)$ The pressure of the gas at a point oscillates in time.

$(B)$ The position of a small layer of the gas oscillates in time.