2
votes
1answer
42 views

Interference and energy question here

So Im reading this material on interference and I noted the following sentence : During the interference of the light of two coherent light sources,the intensity of the radiation changes ...
1
vote
0answers
72 views

Salisbury Screens and Energy Conservation

From Wikipedia on how a Salisbury Screen works: 1. When the radar wave strikes the front surface of the dielectric, it is split into two waves. 2. One wave is reflected from the glossy ...
40
votes
10answers
10k views

What happens to the energy when waves perfectly cancel each other?

What happens to the energy when waves perfectly cancel each other (destructive interference)? It appears that the energy "disappear" but the law of conservation of energy states that it can't be ...
14
votes
4answers
2k views

Energy conservation and interference

I have a problem with energy conservation in case of interfering waves. Imagine two harmonic waves with amplitudes $A$. They both carry energy that is proportional to $A^2$, so the total energy is ...