Question

When interference happens with two monochromatic light waves, which of the following is a characteristic of the amplitude of the resultant wave?

a. it is zero.
b. it is equal to the sum of the amplitudes of the component waves.
c. less than the amplitude of either of the component waves.
d. greater than the amplitude of either of the component waves.

Answer 1

http://en.wikipedia.org/wiki/Interference_(wave_propagation)

note:
[2A] cos (kx- wt) cos(phase angle/2)

Answer 2

"The principle of superposition of waves states that when two or more propagating waves of same type are incident on the same point, the resultant amplitude at that point is equal to the vector sum of the amplitudes of the individual waves."

Is the answer b?

Answer 3

yes