Question

Two wires A and B of same length, radius and same material are in unison. If tension in A is increased by 4%, 4 beat/s are heard, then the frequency of the note produced when they were in unison, will be
1. 50 Hz
2. 100 Hz
3. 150 Hz
4. 200 Hz

Answer 1

Correct Answer - Option 4 : 200 Hz

Let the frequency be n. Then for 4 % increased tension, we have  \(\frac{{104}}{{100}} = {\left( {\frac{{n + 4}}{n}} \right)^2}\)

\(\frac{{n + 4}}{n} = \sqrt {\frac{{104}}{{100}}}\)

Hence, n = 200 Hz