Answer:
Length of the string, l = 0.486 meters
Explanation:
It is given that,
Mass of the string, 
Tension in the string, T = 120 N
Frequency of transverse wave, f = 260 Hz
Wavelength of the wave, 
The speed of a transverse wave (v) is given by :
........(1)
<em>Where,</em>

Also, speed of a wave,
.........(2)
From equation (1) and (2) :


l = 0.486 m
So, the length of the string is 0.486 meters. Hence, this is the required solution.