JEE Main · 2022 · 27 Jun 2022 · Shift 1 · Waves & Sound

WhatsApp Email

An observer moves towards a stationary source of sound with a velocity equal to one-fifth of the velocity of sound. The percentage change in the frequency will be :

(A) $20%$ ✓ Correct
(B) $10%$
(C) $5%$
(D) $0%$

Answer: (A)

Solution

Using the Doppler effect formula for an observer moving towards a stationary source:

f_{0} = (\frac{v + v _{0}}{v}) f_{s}

. With

v_{0} = \frac{v}{5}

, we get

f_{0} = \frac{6}{5} f_{s}

. The percentage change is

\frac{f _{0} - f _{s}}{f _{s}} \times 100 = \frac{1}{5} \times 100 = 20%

JEE Main · 2022 · 27 Jun 2022 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Waves & Sound →

More JEE Main questions on Waves & Sound

Two loudspeakers ( $L_{1}$ and $L_{2}$ ) are placed with a separation of 10 m , as shown in figure. Both speakers are fed with an audio input signal of same frequency with constant volume. A voice recorder, initially at point $A$ , at equidistance to both loud speakers, is m …
JEE Main 2026View solution →
In an open organ pipe $v_{3}$ and $v_{6}$ are $3^{rd}$ and $6^{th}$ harmonic frequencies, respectively. If $v_{6} - v_{3} = 2200$ Hz then length of the pipe is $____$ mm. (Take velocity of sound in air is $330$ m/s.)
JEE Main 2026View solution →
The velocity of sound in air is doubled when the temperature is raised from $0^{\circ} C$ to $α^{\circ} C$ . The value of $α$ is ______.
JEE Main 2026View solution →
The fifth harmonic of a closed organ pipe is found to be in unison with the first harmonic of an open pipe. The ratio of lengths of closed pipe to that of the open pipe is 5/x. The value of x is ____.
JEE Main 2026View solution →
A point source is kept at the center of a spherically enclosed detector. If the volume of the detector increased by 8 times, the intensity will
JEE Main 2026View solution →
The speed of a longitudinal wave in a metallic bar is $400 m / s$ . If the density and Young's modulus of the bar material are increased by $0.5%$ and $1%$ respectively then the speed of the wave is changed approximately to ______ …
JEE Main 2026View solution →