Question

Two perfectly identical wires kept under tension are in unison. When the tension in the wire is increased by 1% then on sounding them together 3 beats are heard in 2 seconds. What is the frequency of each wire?

पर्याय

• 300 Hz

• 400 Hz

• 256 Hz

• 288 Hz

Answer 1

300 Hz

Explanation:

`n = 1/(2l)sqrt(T/m)`

3 beats in 2 sec i.e. 1.5 beats in 1 sec.

`n + 1.5 = 1/(2l)sqrt((1.01T)/m)`

As tension is increased by 10%.

∴ `(n + 1.5)/n = sqrt(1.01) = 1.005`

⇒ n = 300