Two coherent sources are placed two wavelengths apart. Point \(\mathrm{P}\) lies on a nodal line in the interference pattern of the two sources, and point Q lies on an antinodal line.

(a) If one source is turned off, does the energy arriving at P increase, decrease, or remain the same?

(b) If one source is turned off, does the energy arriving at \(\mathrm{Q}\) increase, decrease, or remain the same?

(c) Do your answers depend on which source is turned off?