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Heat transfer processes
Planck law
power radiated in the range of wave length from λ to λ+dλ
dP
λ
=
W
x
W
Planck's constant
h =
6.626E-34
J·s
velocity of light in free space
c =
3E8
m/s
length of emitted wave
λ =
m
x
Å
nm
μm
mm
cm
dm
m
km
n mile
in
ft
yd
area of emitting surface
S =
m
2
x
mm
2
cm
2
dm
2
m
2
km
2
a
ha
in
2
ft
2
yd
2
spectral range
dλ =
m
x
Å
nm
μm
mm
cm
dm
m
km
n mile
in
ft
yd
Boltzmann constant
k =
1.381E-23
J/K
temperature of radiating body
T =
K
x
μK
mK
K
kK
MK
1. Define values of all variables, besides sought quantity
2. Change units if necessary
3. Click "Calculate"