Physics (AS & A Level) · May / June 2021 · Paper 13 · Question 22

A transverse progressive wave of wavelength \(\lambda\) is set up on a stretched string. The graph shows the variation of displacement \(y\) with distance \(x\) at a particular instant of time. The wave has displacement \(+y_1\) at distance \(x = \frac{\lambda}{8}\). What are the next two values of \(x\) where the displacement \(y\) is again equal to \(+y_1\)?

1. A\(\frac{3\lambda}{8}\) and \(\frac{5\lambda}{8}\)
2. B\(\frac{3\lambda}{8}\) and \(\frac{9\lambda}{8}\)
3. C\(\frac{5\lambda}{8}\) and \(\frac{9\lambda}{8}\)
4. D\(\frac{9\lambda}{8}\) and \(\frac{17\lambda}{8}\)

As printed in the paper