Question

$26$ tuning fork are arranged in a line having beat frequency of $4$ between two successive tuning forks. If frequency of last tuning fork is $3$ times that of $1\text{st}$ tuning fork then find the frequency of 1st tuning fork:

• A. 7.5 Hz
• B. 50 Hz
• C. 100 Hz
• D. 125 Hz

Answer 1

Answer: (B)

Beat fréquency of two successive tuning forks is $4$
$\therefore$ difference between the frequencies $=4$
From formula of $A.P.$
$l=a+(n-1)d$
$3f=f+(26-1)\times 4$
$2f=100$
$f=50Hz$