First slide

Beats

Question

Two strings X and Y of a sitar produce a beat frequency 4 Hz. When the tension of the string Y is slightly increased the beat frequency is found to be 2 Hz. If the frequency of X is 300 Hz, then the original frequency of Y was

Moderate

A

296 Hz
B

298 Hz
C

302 Hz
D

304 Hz

Solution

$n_{x} = 300 Hz, n_{y} = ?$
x = beat frequency = 4 Hz, which is decreasing (4 $\to$ 2)
after increasing the tension of the string y.
Also tension of wire y increasing so $n_{y} ↑ (∵ n \propto \sqrt{T})$
Hence $n_{x} - n_{y} ↓ = x ↓$ $\to$ Correct
$n_{y} ↑ - n_{x} = x ↓$ $\to$ Wrong
$\Rightarrow n_{y} = n_{x} - x = 300 - 4 = 296 Hz$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App