The diagram shows a shallow tank viewed from above. The depth of the water is different in the two parts of the tank. The diagram shows the crests and the troughs of a wave that pass from left to right. 2.6 cm boundary Key --- trough -crest 339 (not to scale) The speed of the wave in the left-hand part of the tank is 0.39 m/s. Using information from the diagram, determine the frequency of the wave.
