Source S produces microwaves with a steady amplitude. The microwaves strike a metal screen P and are reflected. A stationary wave is set up between S and P. The wavelength of the microwaves is much less than the separation between S and P. A detector Q is then moved slowly and at a constant speed from S to P. What happens to the amplitude of the signal detected by Q?
- Adecreases steadily
- Bincreases and decreases regularly
- Cincreases steadily
- Dremains constant