Q. 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 $5beats/sec$
A) 1%
B) 2%
C) 3%
D) 4%
Explanation
(b) To produce $5\ beats/sec$ frequency of one wire should be increased up to $505\ Hz.\ i.e.$ increment of 1% in basic frequency.
$n \propto \sqrt{T}$ or $T \propto n^{2} \Rightarrow \frac{\mathrm{\Delta}T}{T} = 2\frac{\mathrm{\Delta}n}{n}$
$\Rightarrow$ percentage change in Tension = $2(1\%) = 2\%$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.