A wave and a crest are travelling toward each other. The crest has an amplitude of
3 cm and the trough has an amplitude of 2
cm. What is the amplitude of the
resulting wave when they interact?
a trough of 1 cm
a crest of 5 cm
a crest of 1 cm
a trough of 5 cm

The magnitude of the poynting vector of a planar electromagnetic wave has an average value of 0.939 w/m^2 . the wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. how much total electromagnetic energy falls on the area during 1.0 minute?