Question

A tuning fork A when sounded with another tuning fork B of frequency $612Hz$ produces 4 beats per second. When A filled , the number,the number of beats reduces to 1 per second . the frequency of A is

• A. $608Hz$
• B. $616Hz$
• C. $618Hz$
• D. $610Hz$

Answer 1

The correct option is A $608Hz$

Let the frequency of A be $f_A$.
Beat frequency $b=|f_A-f_B|$
$\therefore$ $4=|f_A-612|$
On filling the tuning fork, its frequency increases.
Now, beats gets reduced to 1 when A is filled and sounded with B. This implies that frequency of A must be lower than that of B.
Or $4=612-f_A$
$⟹f_A=612-4=608Hz$