JEE Main 2015PhysicsWaves and SoundMediumMCQ

JEE Main 2015 — Waves and Sound Question with Solution

JEE Main 2015 (11 Apr Online)

Question

A source of sound emits sound waves at frequency f0 . It is moving towards an observer with fixed speed vs (vs<v) , where v is the speed of sound in air). If the observer were to move towards the source with speed v0 , one of the following two graphs (A and B) will give the correct variation of the frequency f heard by the observer as v0 is changed.



The variation of f with v0 is given correctly by:

Choose an option

Show full solutionCorrect option: A
Correct answer
AGraph A with slope =f0v-vs

Step-by-step explanation



fapp=v+v0v-vsf0

⇒f=f0v-vsv0+vf0v-vs

On comparing with y=mx+c

m=f0v-vs and c=vf0v-vs

⇒ Graph with +ve slope and +ve intercept.

Practice this on the real CBT interface

Solve this JEE Main question (and the rest of the Waves and Sound chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.

Solve interactively →

About this question

This is a previous-year question from JEE Main 2015, covering the Waves and Sound chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.