CHAPTER 16. OPTICAL PHENOMENA; PROPERTIES OF MATTER 16.4
- What is the energy of the photon?
- What is the frequency of the photon?
- Use table 16.2 to determine the colour of the light.
SOLUTION
Step 1 : What information is given and what do we need to find?
We are given λ = 500× 10 −^9 m and we need to find thephoton’s
energy, frequency and colour.
Step 2 : Use the equation E =hcλto find the photon’s energy
E =
hc
λ
=
(6, 63 × 10 −^34 )× (3× 108 )
500 × 10 −^9
= 3, 98 × 10 −^19 J
The energy of the photon is 3 , 98 × 10 −^19 J.
Step 3 : We know the energy of the photon, now we can use E = hf to
solve for the frequency
E = hf
f =
E
h
=
3. 98 × 10 −^19
6 , 63 × 10 −^34
= 6× 1014 Hz
The frequency of the photon is 6 × 1014 Hz.
Step 4 : Use the table to find the colour of light
The wavelength given in the question is 500 nm. We can see
in the table that green light has wavelengths between 492 - 577
nm. Therefore 500 nm is in this range so the colour of the light is
green.
