4.92 
× 
10 
14 
H 
z 
 
Explanation: 
Let's use the equation for the energy of a photon: 
 
E 
= 
h 
v 
 
E represents the energy of the photon and it has units of Joules (J) 
h represents Planck's constant and it has a value of 
6.626 
× 
10 
− 
34 
J 
× 
s 
v is the frequency and it has units of Hz or 
s 
− 
1 
We know the energy of the photon, and Planck's constant doesn't change so all we have to do is solve for v like this: 
 
E 
h 
= 
v 
 
v 
= 
3.26 
× 
10 
− 
19 
J 
6.626 
× 
10 
− 
34 
J 
× 
s 
 
v 
= 
4.92 
× 
10 
14 
H 
z