In an experiment, to measure the speed of sound by a resonating air column, a tuning fork of frequency 500 Hz is used. The length of the air column is varied by changing the level of water in the resonance tube. Two successive resonances are heard at air columns of length 50 .7 cm and 83 .9 cm . Which of the following statements is (are) true?

The wavelength of the sound wave is 66 .4 cm .

The resonance at 50 .7 cm corresponds to the fundamental harmonic.

Two vehicles, each moving with speed u on the same horizontal straight road, are approaching each other. The wind blows along the road with velocity w . One of these vehicles blows a whistle of frequency f 1 . An observer in the other vehicle hears the frequency of the whistle to be f 2 . The speed of sound in still air is v . The correct statement (s) is (are):

If the wind blows from the source to the observer, f 2 > f 1 .

If the wind blows from the observer to the source, f 2 < f 1 .

If the wind blows from the source to the observer, f 2 < f 1 .

MEDIUM

JEE Main/Advance

IMPORTANT

Earn 100

Two adjacent resonance frequencies of an open organ pipe are $1800 Hz$ and $2100 Hz$ . Find the length of the tube. The speed of sound in the air is $330 m s^{- 1}$ .

Important Questions on Sound Waves

MEDIUM

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 12

A closed organ pipe of length

l = 100 cm

is cut into two unequal pieces. The fundamental frequency of the new closed organ pipe piece is found to be the same as the frequency of the first overtone of the open organ pipe piece. Determine the length of the two pieces and the fundamental tone of the open pipe piece. Take velocity of sound

= 320 m s^{- 1}

MEDIUM

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 13

Find the number of possible natural oscillations of air column in a pipe whose frequencies lie below

f_{0} = 1250 Hz .

The length of the pipe is

l = 85 cm .

The velocity of sound is

v = 340 m s^{- 1} .

Consider the two cases :
(a) The pipe is closed from one end (b) The pipe is opened from both ends.

MEDIUM

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 14

In a resonance tube experiment to determine the speed of sound in air, a pipe of diameter

5 cm

is used. The air column in pipe resonates with a tuning fork of frequency

480 Hz

when the minimum length of the air column is

16 cm .

If the speed of sound in air at room

temperature = 6 η (in m \sec^{- 1} .) Find η

MEDIUM

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 15

A person hums in a well and finds strong resonance at frequencies

60 Hz

100 Hz

and

140 Hz

. What is the fundamental frequency of the well? Explain? How deep is the well?

(Velocity of sound = 344 m s^{- 1})

EASY

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 16

A source of sound with adjustable frequency produces

2

beats per second with a tuning fork when its frequency is either

476 Hz

480 Hz .

What is the frequency of the tuning fork?

MEDIUM

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 17

An observer rides with a sound source of frequency $f$ and moves with velocity $v$ towards a large vertical wall. Considering the velocity of sound waves as $c$ , find:

$(i)$ The number of waves striking the surface of the wall per second.
$(ii)$ The wavelength of the reflected wave.
$(iii)$ The frequency of a reflected wave as observed by an observer.
$(iv)$ Beat frequency heard by the observer.

MEDIUM

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 18

A stationary source emits a single frequency sound. A wall approaches it with velocity

u = 33 cm s^{- 1}

. The propagation velocity of sound in the medium is

v = 330 m s^{- 1}

. In what way and how much, in percent, does the wavelength of sound change on reflection from the wall?

HARD

JEE Main/Advance

IMPORTANT

Alpha Question Bank for Engineering: Physics>Chapter 21 - Sound Waves>Exercise - 1>Q 19

A source of sonic oscillations with frequency

f_{0} = 1000 Hz

, moves at right angles to the wall with a velocity

u = 0.17

m s^{- 1}

. Two stationary receivers

R_{1}

and

R_{2}

are located on a straight line, coinciding with the trajectory of the source, in the following succession:

R_{1} -

source

- R_{2} -

wall. Which receiver registers the beatings and what is the beat frequency? The velocity of sound is equal to

v = 340 m s^{- 1}

Two adjacent resonance frequencies of an open organ pipe are 1800 Hz and 2100 Hz. Find the length of the tube. The speed of sound in the air is 330 m s-1.

Important Questions on Sound Waves

Learn and Prepare for any exam you want !

Two adjacent resonance frequencies of an open organ pipe are $1800 Hz$ and $2100 Hz$ . Find the length of the tube. The speed of sound in the air is $330 m s^{- 1}$ .