63. Let the power of the laser beam be P and the energy of each photon emitted be E. Then, the rate of
photon emission is
R
=
P
E
=
P
hc/λ
=
P λ
hc
=
(5.0
× 10
−3
W)(0.80
× 10
−6
m)
(6.63
× 10
−34
J
·s)(2.998 × 10
8
m/s)
=
2.0
× 10
16
s
−1
.