Consider a laser pointer that emits red light with wavelength 650 nm. This light is used for a photoelectric effect experiment where the anode in the evacuated glass tube is made up of a material that has work function equal to 1 eV. 1. What is the energy of an individual photon that comes out of the laser pointer?

The energy of an individual photon that comes out of the laser pointer is 1.91 eV

Explanation:

The energy of a photon can be obtained using the expression below

E = hc/λ

where E is the energy;

h is the Planck's constant  = 6.626 x 10-34 Js;

c is the speed of light = 3.00 x m/s (speed of light);

λ is the wavelength = 650 nm =650 x m.

E = (6.626 x 10-34 Js) x (3.00 x m/s) /650 x m

E = 3.058 x J

1 joule = 6.242 x eV

3.058 x J = 3.058 x J x 6.242 x eV = 1.91 eV

Therefore the energy of an individual photon that comes out of the laser pointer is 1.91 eV