Learn

Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 17 March 2021, Shift 2, Physics Q3

Question 3 of 90 in this shift, Physics question 3 of 30, Section A.

A sound wave of frequency 245 Hz travels with the speed of 300 ms−1\mathrm{ms^{-1}} along the positive x-axis. Each point of the wave moves to and fro through a total distance of 6 cm. What will be the mathematical expression of this travelling wave ?
  1. (1)Y(x, t)=0.03 [ sin 5.1x−(0.2×103)t ]\mathrm{Y(x,\ t)=0.03\ [\ sin\ 5.1x-(0.2\times10^3)t\ ]}
  2. (2)Y(x, t)=0.03 [ sin 5.1x−(1.5×103)t ]\mathrm{Y(x,\ t)=0.03\ [\ sin\ 5.1x-(1.5\times10^3)t\ ]}Official answer
  3. (3)Y(x, t)=0.06 [ sin 5.1x−(1.5×103)t ]\mathrm{Y(x,\ t)=0.06\ [\ sin\ 5.1x-(1.5\times10^3)t\ ]}
  4. (4)Y(x, t)=0.06 [ sin 0.8x−(0.5×103)t ]\mathrm{Y(x,\ t)=0.06\ [\ sin\ 0.8x-(0.5\times10^3)t\ ]}

Official answer

Option 2

NTA final key.

Chapter
Waves
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.