A tall hill lies in the way of the straight-line route between a transmitter of radio waves and a receiver, as illustrated. The receiver detects the signal from the transmitter even though the radio waves do not pass through the hill. Which row is correct?
- Adiffraction round the hill; longer wavelengths
- Bdiffraction round the hill; shorter wavelengths
- Crefraction round the hill; longer wavelengths
- Drefraction round the hill; shorter wavelengths