Physics (AS & A Level) · May / June 2021 · Paper 13 · Question 29

A double-slit interference pattern using red light of wavelength 7.0 × 10⁻⁷ m has a fringe spacing of 3.5 mm. Which fringe spacing would be observed for the same arrangement of apparatus but using blue light of wavelength 4.5 × 10⁻⁷ m?

1. A2.3 mm
2. B3.5 mm
3. C5.4 mm
4. D9.0 mm

As printed in the paper