Physics (AS & A Level) · Oct / Nov 2017 · Paper 11 · Question 28

Coherent waves are produced at P and at Q and travel outwards in all directions. The line RS is half-way between P and Q and perpendicular to the line joining P and Q. The distance RS is much greater than the distance PQ. Along which of the lines shown is an interference pattern observed?

1. Aboth RS and XY
2. BRS only
3. CXY only
4. Dneither RS nor XY

As printed in the paper