671nm
Explanation:
Wavelength relates to frequency as follows:
λ
=
v
f
in which
f
is the frequency,
v
is the speed of light, and
λ
is the wavelength.
Filling this in for the example:
v
=
3
⋅
10
8
m
s
f
=
4.47
⋅
10
14
H
z
=
4.47
⋅
10
14
s
−
1
λ
=
3
⋅
10
8
m
s
4.47
⋅
10
14
s
−
1
=
6.71
⋅
10
−
7
m
from m to nm is
⋅
10
9
So the wavelength is:
671
n
m
(red light).
