11. The diagram to the right shows a harmonic of a standing wave on a vibrating string.
Open the image for the rest :)

(a) Fourth harmonic

(b) 2 wavelengths

(c) wavelength = 1  m

Explanation:

11.

(a) It is fourth harmonic.

(b) The distance between the two consecutive nodes is half of wavelength, so there are two wavelength.

(c) The distance between the two consecutive node or the antinode is half of wavelength.

So, wavelength = 2/2 = 1 m

i guess it’s a and b