Jim Kelley wrote:
Cecil Moore wrote:
If the intensity of one wave is P, the intensity of the
bright rings will be 4P and the intensity of the dark
rings will be zero.

That's right. And we know that intensity is proportional to the square
of the EM field, so if P=9 then field=3. When there are two such EM
fields superposed, then we have 3+3 squared which is four times greater
than 3 squared. And owing to this supposed 'inequality', we have the
sophomoric (literally) notion that there is "extra" energy which must
come from somewhere else.

The intensity is watts/unit-area, i.e. real energy.
If the intensity of the bright rings is 4P there is
indeed greater than average energy which requires a
zero P dark ring somewhere else in order to
average out to 2P. The "extra" energy in the bright
rings comes from the dark rings. The conservation of
energy principle allows nothing else. It is not a
sophomoric notion. It is the laws of physics in action.
--
73, Cecil http://www.w5dxp.com