S1 and S2 are two stationary sources of sound, of frequencies 320 Hz and 324 Hz respectively, placed at a good distance from each other. The velocity with which an observer should walk towards S1 along the line joining S1 and S2 in order that he may hear no beats, is about (velocity of sound = 332 ms–1):


Correct option is



To hear no beats, the beat frequency has to be 4 Hz. Using the formula, 


And putting n = 4, f = average frequency = 322 Hz.

We get u = 2 m/s.



A uniform rope of mass 6 kg hangs vertically from a rigid support. A block of mass 2 kg is attached to the free end of the rope. A transverse pulse of wavelength 0.06 m is produced at the lower end of the rope. The wavelength of the pulse when it reaches the top is (in m):


A tuning fork of frequency 256 Hz is excited and held at the mouth of a resonance column of frequency 254 Hz. Choose the correct statement:


A man facing a wall holds a tuning fork of frequency 256 Hz between himself and a vertical wall. He moves the tuning fork towards the wall with a velocity 1/100 of the velocity of sound. The number of beats heard per minute would be:


In a good tuning fork:


A flat horizontal platform moves up and down in SHM with an amplitude of 1 cm. A small object is placed on the platform. What is the maximum frequency the platform can have, if the object is not to separate from it during any part of motion?


When a tuning fork is vibrating, the vibrations of the two prongs:


One of the prongs of a tuning fork is broken. The intensity of sound produced by it will:


A sound wave of wavelength λ travels towards the right horizontally with a velocity v. It strikes and reflects from a vertical plane surface, travelling at a speed v towards the left. The number of positive crests striking in a time interval of three seconds on the wall is:


A tuning fork is set into vibrations and then it is held with its stem resting on a table. How will the duration of its vibrations be affected?


Which of the following emits a pure sine wave?