Question

0. Two sources A and B are sounding notes of frequency 660 Hz. A listener moves from A to B with a constant
velocity u. If the speed of sound is 330 m/s, what must be the value of u so that he hears 8 beats per second?​

Answer 1

• Value of u so that he hears 8 beats per second is 2 m/sec.

Given

Frequency = 660 Hz

Velocity of listener = u

Speed of sound = 330 m/ sec

Apparent frequency of sound heard by the observer from source A is:

n₁ = { v-v₀ / v+vs } n = { v-u / v + vs } n where n is the frequency and n₁ is the apparent frequency.

Apparent frequency of sound heard by the observer from source B:

n₂ = { v+v₀ / v-vs } n = { v+u / v-vs } n

Number of beats given = 8

So, n₂ - n₁ = 8, So by putting the value of n₁ and n₂ into it, we get,

{ v+u / v-vs } n - { v-u / v + vs } n = 8

{ 330 + u/ 330 - 0 } (660) - { 330 - u/ 330 + 0 } (660) = 8

2 × 660 u / 330 = 8

4u = 8

u = 2 m/sec.

Regards

Answer 2

Answer:

Explanation:

i hope its clear!!