Question

Two identical piano wires, kept under the same tension $T$ have a fundamental frequency of $600 \,Hz$. The fractional increase in the tension of one of the wires which will lead to occurrence of $6$ beat's when both the wires oscillate together would be

• A. 0.01
• B. 0.02
• C. 0.03
• D. 0.04

Answer 1

Answer: (B)

0.02

Answer 2

$n \propto \sqrt{ T }$
$\frac{\Delta n }{ n }=\frac{1}{2} \frac{\Delta T }{ T }$
$\frac{\Delta T }{ T }=2 \times \frac{\Delta n }{ n }=2 \times \frac{6}{600}$
$=0.02$