DOC.
42
SPECIAL AND
GENERAL RELATIVITY 299
54
Relativity
way
this result becomes modified
in
the
general theory
of
relativity.
Note.-With
the advent
of nuclear transformation
processes,
which result
from
the
bombardment of elements
by
a-particles, protons,
deuterons,
neutrons or
y-rays,
the
equivalence
of
mass
and
energy expressed
by
the relation
E
=
mc2
has
been
amply
confirmed.
The
sum
of the
reacting
masses, together
with the
mass
equivalent
of the
kinetic
energy
of the
bombarding particle (or
photon),
is
always
greater
than the
sum
of the
resulting
masses.
The
difference
is
the
equivalent
mass
of the kinetic
energy
of the
particles generated,
or
of the released
electromagnetic energy (y-photons).
In
the
same way,
the
mass
of
a
spontaneously
disintegrating
radioactive
atom is always
greater
than the
sum
of the
masses
of the
resulting atoms
by
the
mass
equivalent
of
the kinetic
energy
of the
particles generated
(or
of the
photonic energy).
Measure-
ments
of the
energy
of the
rays
emitted
in
nuclear
reactions, in
combination with the
equations
of such
reactions,
render
it
possible to
evaluate atomic
weights to
a high
degree
of
accuracy.
R. W. L.