part of the spectrum.
Stephan-Bolpsman law. Based on the results of the experiment, I. Stefan (1879)
determined the following law: the radiation property of an absolute black body is
directly proportional to the fourth degree of its absolute temperature. A. Bolsman
theoretically proved this law in 1884.
1
4
0
0
0
0
(
) ,
100
T
Е
J d
C
(10.7)
where S
0
is the absolute blackbody radiation coefficient. [C
0
=5.67W/(m
2
K
4
)]; T is
the temperature of
the body surface, K.
This law can also be written in the following forms:
E
0
=G
0
T
4
,
(10.8)
For gray objects:
4
4
0
0
(
)
(
)
100
100
T
T
E
E
C
C
10.9
where: G
0
– 5.67∙10-8W/(m
2
∙K) – Stefan's constant; S - radiation of a gray body;
ɛ=E/E
0
is the blackness level of the gray matter.
Kirchhoff's law. In 1882, G. Kirchhoff studied
the difference between the
absorption and distribution of heat rays of absolute
black and gray bodies and
discovered the following law:
3
0
1
2
0
1
2
3
0
......
( ),
E
E
E
E
E T
A
A
A
A
