Q. A tuning fork gives 4 beats with 50 cm length of a sonometer wire. If the length of the wire is shortened by 1 cm, the number of beats is still the same. The frequency of the fork is
A) 396
B) 400
C) 404
D) 384
Explanation
(a) $n \propto \frac{1}{l} \Rightarrow n_{1}l_{1} = n_{2}l_{2} \Rightarrow (n + 4)49 = (n - 4)50 \Rightarrow n = 396$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.