Energy and interference.

[mprm86]

What happens with energy after two or more waves interfere destructively? Is there a loss of energy?

Thanks.

[ZapperZ]

Believe it or not, as the case for many seemingly-simple problem, the answer to this can be rather lengthy. For example, if you are talking about two oppositely-moving overlapping waves, then the energy conservation comes in because the location of destructive interference is still moving (i.e. it may have an instantaneous zero amplitude, but it still has a kinetic energy).

A very thorough discussion of this can be found in a paper written by N. Gauthier "What happens to energy and momentum when two oppositely-moving wave pulses overlap", Am. J. Phys. v.71, p.787 (2003).

Zz.