The wave pattern on a stretched string is shown in the figure. Interpret what kind of wave this is and find its wavelength.

(N/A) The given figure shows a standing wave (or stationary wave) because the nodes (points with zero displacement) remain fixed at specific positions $x = 10, 20, 30, 40 \text{ cm}$ for all times $t$.
The distance between two consecutive nodes is equal to $\frac{\lambda}{2}$.
From the figure,the distance between two consecutive nodes is:
$\frac{\lambda}{2} = 20 \text{ cm} - 10 \text{ cm} = 10 \text{ cm}$.
Therefore,the wavelength $\lambda$ is:
$\lambda = 2 \times 10 \text{ cm} = 20 \text{ cm}$.