Question

The tension in a piano wire is $10N$. The tension in a piano wire to produce a node of double frequency is

• A. $20N$
• B. $40N$
• C. $10N$
• D. $120N$

Answer 1

The correct option is B $40N$

For frequency of oscillation of wire $n\propto \sqrt{T}$.

Here $T$ is tension in the wire. In order to increase frequency twice, tension needs to be made $4$ times.

So, new tension must be $4\times 10=40N$