RADIATIVE EQUILIBRIUM
113
v' radiation corresponds to the temperature drop in 2 cm. The net outward
flow for v' is thus only one-hundredth of that of v".
If v' represents 1 per cent, of the radiation and v" the remaining 99 per
cent., the absorption-line at v' will double the total amount of absorption
and emission going on; although constituting but a small part of the
radiation it does as much business as all the rest put together. This means
that Jc t is doubled. But as regards opacity the effect is that 1 per cent, of
the radiation suffers an almost complete check, and the rest flows through
as before. Hence & 2 is only increased 1 per cent.