G L Mittal and TARUN MITTAL Solutions for Chapter: Superposition of Waves-1 : Interference and Beats, Exercise 3: FOR DIFFERENT COMPETITIVE EXAMINATIONS

When two tuning forks A and B are sounded together, $x$ beats per second are heard. The frequency of A is $n$ . Now, when one prong of the fork B is loaded with a little wax, the number of beats per second decreases. The frequency of the fork B is :

A source of unknown frequency produces $8$ beats per second with a source of $250 \mathrm{Hz}$ and $12$beats per second with a source of $270 \mathrm{Hz}$ . The frequency $n$ of the unknown source is :

When two tuning forks (fork $1$ and fork $2$) are sounded simultaneously, $4$ beats per second are heard. Now, some tape is attached on the prong of fork $2$. When the tuning forks are sounded again, $6$ beats per second are heard. If the frequency of the fork 1 is 200 Hz., then original frequency of fork 2 is :

A source of frequency $n$ gives $5$ beats ${\mathrm{s}}^{-1}$, when sounded with another source of frequency $200 {\mathrm{s}}^{-1}$. The second harmonic $\left(2n\right)$ of the first source gives $10$ beats ${\mathrm{s}}^{-1}$ when sounded with a source of frequency $420 {\mathrm{s}}^{-1}$. Then, $n$ is equal to

Three sound waves of equal amplitudes have frequencies $\left(n-1\right), n, \left(n+1\right)$. They superimpose to give beats. The number of beats produced per second will be :

The number of beats produced per second by oscillations $y_1=a \sin \left(320\mathrm{\pi t}\right)$ and $y_2=a \sin \left(326\mathrm{\pi t}\right)$ is : 

Two sounding bodies producing progressive waves given by : $y_1=4 \sin \left(400\mathrm{\pi t}\right)$ and $y_2=3 \sin \left(404\mathrm{\pi t}\right)$ are situated very near to the ears of a person. He will hear : 

Three sources of equal intensities and frequencies $400, 401, 402 Hz$  are sounded simultaneously. The frequency of beats is :