Question

When the length of the string is 100 cm, it gives 5 beats with a tuning fork. When the length of the wire is charged to 80 cm again it gives 5 beats with same tuning fork. The frequency of the fork is

Answer 1

Given that,

Length $l_1=100m$

Length $l_2=80m$

We know that,

Frequency $=n$

Now,

$\frac{n+5}{n-5}=\frac{80}{100}$

$100n+500=80n-400$

$20n=900$

$n=45Hz$

Hence, the frequency of fork is $45Hz$