Diagram 1 shows a ripple tank experiment in which plane waves are diffracted through a narrow slit in a metal sheet. Diagram 2 shows the same tank with a slit of greater width. In each case, the pattern of the waves incident on the slit and the emergent pattern are shown.
Which action would cause the waves in diagram 1 to be diffracted less and so produce an emergent pattern closer to that shown in diagram 2?
increasing the speed of the waves by making the water in the tank deeper
reducing the length of the vibrating bar
increasing the frequency of vibration of the bar
reducing the amplitude of vibration of the bar
