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

• A. 1%
• B. 2%
• C. 3%
• D. 4%

Answer 1

Answer: (B)

2%

Answer 2

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

$n \propto \sqrt{T}$ or $T \propto n^{2}$⇒ $\frac{\Delta T}{T} = 2\frac{\Delta n}{n}$

⇒ percentage change in Tension =$2(1\%) = 2\%$