A string, fixed at both ends, vibrates in a resonant mode with a separation of 20 cm between the consecutive nodes. For the next higher resonant frequency, this separation is reduced to 16 cm. Find the length of the string.

80 cm

Suppose, there are n loops initially and length of loop is L.


So,


So, Ll=


2=



Computing this we get,


n=4


So, length of the string is,


1