Question

Two similar sonometer wires given fundamental frequencies of 500Hz. These have same tensions. By what amount the tension be increased in one wire so that the two wires produce 5 beats/sec

[RPET 1999]

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

To produce 5 beats/sec. Frequency of one wire should be increase up to 505 Hz. i.e. increment of $1\%$ in basic frequency.

$n\infty \sqrt{T}orT\infty n^2\Rightarrow \frac{\Delta T}{T}=2\frac{\Delta n}{n}$

$\Rightarrow$ percentage change in tension = $2\left(1\%\right)=2\%$