Physics (AS & A Level) · Feb / March 2017 · Paper 12 · Question 28

A monochromatic plane wave of speed c and wavelength λ is diffracted at a small aperture. The diagram illustrates successive wavefronts. After what time will some portion of the wavefront GH reach point P?

1. A\frac{3\lambda}{2c}
2. B\frac{2\lambda}{c}
3. C\frac{3\lambda}{c}
4. D\frac{4\lambda}{c}

As printed in the paper