Question

A standing wave on a string of length L = 2 m has a wavelength λ = 0.5 m. The strings oscillates in its:

Answer 1

The wavelength of a standing wave in a string is given as follows (see https://www.physicsclassroom.com/class/waves/Lesson-4/Mathematics-of-Standing-Waves):

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

where $n$ is the number of harmonic. Expressing $n$, get:

$$n = \dfrac{2L}{\lambda} = \dfrac{2\cdot 2m}{0.5m} = 8$$

Answer. The strings oscillates in its 8th harmonic.