DOC. 34 THEORY OF LIGHT PRODUCTION 357
206
A. Einstein. Theorie
der
Lichterzeugung
u.
Lichtabsorption.
Spannungsdifferenz
V12
der
beiden Metalle die
Gleichung
gelten:
-
Fn
=
ri
~
rt
=
if ß?i
~
**)»
oder, wenn
V12
in
Volt
gemessen
wird:
V12 =
4,2.10-15(v2-v1).
In
dieser Formel
ist
folgender,
im
großen ganzen
jeden-
falls
gültige
Satz
enthalten: Je stärker
elektropositiv
ein Metall
ist,
desto kleiner
ist
die unterste wirksame
Lichtfrequenz
für
[23]
das betreffende Metall.
Es
wäre
von
hohem
Interesse
zu
wissen,
ob die Formel auch in
quantitativer
Beziehung
als
Ausdruck der
Tatsachen
zu
betrachten ist.
[24]
Bern,
März 1906.
(Eingegangen
13.
Marz
1906.)
Published in Annalen
der
Physik
20
(1906):
199-206.
Dated Bern March
1906,
received
13
March
1906,
published 11 May
1906.
A
set
of
page proofs,
with several corrections
in Einstein’s
hand,
was given
to
Einstein’s Bern
acquaintance,
Adolf
Gasser
(Gasser Nachlaß,
Basel).
Einstein’s corrections
are
indicated
in
the
relevant
notes
below.
[1]
Einstein
1905i
(Doc.
14).
[2]
See
Einstein
1905i
(Doc.
14), pp.
133-
134,
for
Einstein’s derivation
of
the
energy
dis-
tribution
of
black-body
radiation.
[3]
That
is,
for
large
values
of
v/T. See Ein-
stein 1905i
(Doc. 14),
p.
139.
[4]
Planck
1901a. On the proof
of
this
page
“A. Einstein”
appears
in fn. 2
instead
of “M.
Planck.”
The
error
is not corrected in the
proof.
Planck’s
formula
is
eq. (12)
of
the
page
cited.
[5]
Comparison
between this
expression
and
Planck
1901a,
p.
561,
eq. (12),
shows that
a
=
8h/c3,
where
c
is
the
speed
of
light (L
in Ein-
stein’s
notation)
and
ß
=
h/k
=
hN/R.
[6]
Planck
1900a.
[7]
Einstein
is
referring
to
Planck’s
“natural
radiation”
(“natürliche Strahlung”). For Ein-
stein’s
definition,
see
Einstein 1905i
(Doc. 14),
p.
135,
fn.
2.
[8]
This
equation
does
not
appear on p.
99
of
Planck 1900a.
It
can
be derived from
equations
on pp.
99 and 111. Planck first
published
the
equation
in
Planck
1900e,
p.
241.
[9]
This
is
substantially
Einstein’s model in
Einstein
1905i
(Doc.
14),
§
1.
[10]
See Einstein 1905i
(Doc.
14), p.
136.
[11]
Einstein
1903
(Doc. 4).
[12]
An
equation equivalent
to
eq.
(4) is
de-
rived
in
Einstein 1903
(Doc.
4),
§ 6,
p.
182.
[13]
See
Einstein
1903
(Doc.
4),
pp.
174-178.
[14]
The limits on
the integral
here
and in
eq.
(5a)
should be H and
H
+
AH, and
AH
in the
next lines
of
text should be AH.
[15]
For
details
of
the
calculation, see, e.g.,
Kuhn
1978,
pp.
183-184.
[16]
In
Planck
1900d,
p.
240,
and
Planck
1901a,
p.
557,
Planck refers to
W
as
“the
num-
ber of
all
possible
complexions”
(“die Anzahl