Question

A tuning fork and a sonometer wire were sounded together and produce 4 beats per second. When the length of sonometer wire is 95 cm or 100 cm, the frequency of the tuning fork is

• A. 156 Hz
• B. 152 Hz
• C. 148 Hz
• D. 160 Hz

Answer 1

The correct option is A

156 Hz

Probable frequencies of tuning fork be n+4 or n-4

Frequency of sonometer wire $n\infty$ < /span > $\frac{1}{l}$

$\therefore \frac{n+4}{n-4}=\frac{100}{95}or95(n+4)=100(n-4)$

or 95n + 380 = 100 n - 400 or 5n = 780 or n = 156