Question

The laser used to read information from a compact disk has a

wavelength of 780 nm. What is the
energy associated with one photon of this radiation?

Answer 1

The energy associated with one photon of laser light with a wavelength of 780 nm from a compact disk is 2.55 x 10^-19 joules.

Step-by-step explanation:

To calculate the energy associated with one photon of light from a compact disk laser with a wavelength of 780 nm, we can use the formula E = hν, where E is the energy of a photon, h is Planck's constant (6.626 x 10-34 Js), and ν (nu) is the frequency of the light. The frequency can be found using the speed of light, c = 3.00 x 108 m/s, divided by the wavelength of the light in meters. So first, we convert the wavelength from nanometers to meters by dividing by 1 x 109.

ν = c / λ = (3.00 x 108 m/s) / (780 nm x 1x10-9 nm/m) = 3.85 x 1014 Hz

E = hν = (6.626 x 10-34 J·s)(3.85 x 1014 Hz) = 2.55 x 10-19 J

The energy of a photon with a wavelength of 780 nm is 2.55 x 10-19 joules.