Sunlight
strikes the Earth, just outside its atmosphere,
with an intensity of
|
Solution: Click For PDF Version For the plane electromagnetic wave, the magnitude of the Poynting vector, S, is
which can
also be written, using
where S,
E, and B
are instantaneous values at the observation
point. The time average
The time
average of
As the intensity of the sunlight outside the Earth’s atmosphere is given to be
The electric
field
|
.
Assuming sunlight to be a plane wave,
we have to calculate
(a)
and (b)
for it.
,
is also known as the intensity I
of the wave. We have
over any whole number of cycles is
.
Therefore,
,
And
the magnetic field associated with the wave will be given by