JEE Main 2021PhysicsWaves and SoundMediumNumerical

JEE Main 2021 — Waves and Sound Question with Solution

JEE Main 2021 (26 Aug Shift 2)

Question

Two waves are simultaneously passing through a string and their equations are : y1=A1sink(x-vt),y2=A2sinkx-vt+x0. Given amplitudes A1=12 mm and A2=5 mm,  x0=3.5 cm and wave number k=6.28 cm-1. The amplitude of resulting wave will be _____ mm.

Enter your answer

Show full solutionCorrect answer: 7
Correct answer
7

Step-by-step explanation

Δϕ=kx0=2πλx0=2π×3.5  λ=2πk=1

=2π×3510=7π

AR=122+52+2×12×5×cos(7π)=(12-5)2=7 mm

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 2021, 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.