Question

A vibrating string produces $2$ beats $persecond$ when sounded together with a tuning fork of frequency $256Hz$. On increasing the tension in the string the beats produced $persecond$ are $3$. The initial frequency of the string may have been:

• A. $253Hz$
• B. $254Hz$
• C. $258Hz$
• D. $259Hz$

Answer 1

The correct option is C $258Hz$

As initially beat was $2$, the frequency of the string could have been either $258$ or $254Hz$.
However, as on increasing the tension in the string, beats increases and also Increase in tension will causes frequency to increase, the initial frequency of the string was greater than that of the tuning fork.
So, initial frequency of the string $=258Hz$