Medium MCQ +4 / -1 PYQ · JEE Mains 2021

A tuning fork A of unknown frequency produces 5 beats/s with a fork of known frequency 340 Hz. When fork A is filed, the beat frequency decreases to 2 beats/s. What is the frequency of fork A?

  1. A 335 Hz Correct answer
  2. B 345 Hz
  3. C 338 Hz
  4. D 342 Hz

Solution

Initially beat frequency = 5Hz<br><br>so, $\rho$<sub>A</sub> = 340 $\pm$ 5 = 345 Hz, or 335 Hz<br><br>after filing frequency increases slightly so, new value of frequency of A &gt; $\rho$<sub>A</sub><br><br>Now, beat frequency = 2Hz<br><br>$\Rightarrow$ new $\rho$<sub>A</sub> = 340 $\pm$ 2 = 342 Hz, or 338 Hz<br><br>hence, original frequency of A is $\rho$<sub>A</sub> = 335 Hz

About this question

Subject: Physics · Chapter: Waves · Topic: Wave Motion and Types

This question is part of PrepWiser's free JEE Main question bank. 88 more solved questions on Waves are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →