Search any question & find its solution
Question:
Answered & Verified by Expert
A tuning fork $A$ produces 4 beats/s with another tuning fork $B$ of frequency 320 Hz . On filing one of the prongs of $A, 4$ beats $/ \mathrm{s}$ are again heard when sounded with the same fork $B$. Then, the frequency of the fork $A$ before filing is
Options:
Solution:
2617 Upvotes
Verified Answer
The correct answer is:
320 Hz
There are 4 beats between $A$ and $B$, therefore the possible frequencies of $A$ are 316 or 324 that is $(320 \pm 4) \mathrm{Hz}$.
When the prong of $A$ is filed, its frequency becomes greater than the original frequency. If we assume that original frequency of $A$ is 324 then on filing its frequency will be greater than 324 . The beats between $A$ and $B$ will be more than 4 . But it is given that the beats are again 4 , therefore, 324 is not possible.
Therefore, required frequency must be 316 Hz . (This is true, because on filing the frequency may increase so as to give 4 beats with $B$ of frequency 320 Hz).
When the prong of $A$ is filed, its frequency becomes greater than the original frequency. If we assume that original frequency of $A$ is 324 then on filing its frequency will be greater than 324 . The beats between $A$ and $B$ will be more than 4 . But it is given that the beats are again 4 , therefore, 324 is not possible.
Therefore, required frequency must be 316 Hz . (This is true, because on filing the frequency may increase so as to give 4 beats with $B$ of frequency 320 Hz).
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.