Question

A 6 m long rope is stretched between two supports with a tension that makes the speed of transverse waves 120 m/s. What is the wavelength of the fourth harmonic?
a. 3m

b. 6m

c. 12m

d. 40m

Answer 1

If rope is given in fourth harmonic

then it means that rope will have FOUR loops

One loop is always length of half wavelength

SO total length of the rope is given as

$L = n\frac{\lambda}{2}$

now here we know

L = 6 m

n = Fourth Harmonic

$6 = 4 * \frac{\lambda}{2}$

now we have

$\lambda = 3 m$

so option A is correct