Question

Solution

Correct option is

300

The tuning fork is a source moving away from the observer, while the sound reflected from the wall is moving towards the observer. Thus, we have two sources of the same frequency, one moving away and the other moving towards the observer with the same velocity. If v is the velocity of sound, vs the velocity of the source, the apparent frequency difference is:  we get number of beats = frequency difference = 5/sec = 300 per minute.

SIMILAR QUESTIONS

Q1

The speed of sound waves in dry air at NTP is 332 m/sec. Assuming air to be composed of oxygen and nitrogen in the ratio 1:4 and the densities of oxygen and nitrogen at NTP to be in the ratio 8:7, the velocity of sound in oxygen will be equal to:

Q2

The speed of sound waves in a mixture of helium and neon at 300 K and at a pressure of 76 cm of Hg was found to be 758 m/sec. The densities of helium and neon are respectively 0.1785 and 0.8999 g/litre and γ of mixture is 1.667. What is the ratio of He and Ne in the mixture?

Q3

The number of possible overtones of air column in a closed pipe of length 83.2 cm and of diameter 6 cm whose frequencies lie below 1000 Hz will be [velocity of sound = 340 m/s]:

Q4

Two stars P and Q have slightly different surface temperatures TP and TQrespectively, with TP > TQ. Both stars are receding from the earth with speeds vP and vQ relative to the earth. The wavelength of light at which they radiate the maximum energy is found to be same for both:

Q5

In a resonance column experiment, a long tube, open at the top, is calmed vertically. By a separate device, water level inside the tube can be moved up or down. The section of the tube from the open end to the water level acts as a closed organ pipe. A vibrating tuning fork is held above the open end, and the water level is gradually pushed down. The first and the second resonances occur when the water level is 24.1 cm and 74.1 cm respectively below the open end. The diameter of the tube is:

Q6

A wave represented by the equation is superimposed on another wave to form a stationary wave such that the point x = 0 is a node. The equation for the other wave is:

Q7

The amplitude of a wave disturbance propagating in the positive x-direction is given by at time t = 0 and by at t = 2 seconds, where x and y are in metres. The shape of the wave disturbance does not change during the propagation. The velocity of the wave is:

Q8

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):

Q9

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:

Q10

In a good tuning fork: