Physics (AS & A Level) · Oct / Nov 2023 · Paper 11 · Question 29

A beam of red light of wavelength 720 nm is incident normally on a diffraction grating and produces a diffraction pattern on a screen placed parallel to the grating. The beam of red light is replaced with a beam of electromagnetic radiation of wavelength X, which is incident normally on the same diffraction grating. The third-order maximum for the electromagnetic radiation of wavelength X is at the same position on the screen as the second-order maximum for the red light. What is wavelength X?

1. A480 nm
2. B540 nm
3. C960 nm
4. D1100 nm

As printed in the paper