Q. Two identical wires have the same fundamental frequency of $400\ Hz$ when kept under the same tension. If the tension in one wire is increased by 2% the number of beats produced will be
A) 4
B) 2
C) 8
D) 1
Explanation
(a) $n \propto \sqrt{T} \Rightarrow \frac{\mathrm{\Delta}n}{n} = \frac{1}{2}\frac{\mathrm{\Delta}T}{T}$
Beat frequency
$= \mathrm{\Delta}n = \left( \frac{1}{2}\frac{\mathrm{\Delta}T}{T} \right)n = \frac{1}{2} \times \frac{2}{100} \times 400 = 4$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.