To show a stationary wave, two microwave transmitters, each producing waves of wavelength $4\,\text{cm}$, are positioned opposite one another, as illustrated. A detector is then dragged along a straight path between the transmitters. It finds positions where the signal is greatest and where it is least. The detector is a distance $d$ from the transmitter on the left. Assume that both transmitters lie at antinodes of the stationary wave. Which row gives a value of $d$ for a maximum and for a minimum?
Physics 9702 · AS & A Level · Stationary waves