A crystal emits a light of wavelength 720.0 nm. What is the light's energy in joules of a mole photons

Question

Quizplus · Accepted Answer

The energy of a photon of light is given by the equation E = hc/λ, where h is Planck's constant (6.626 x 10^-34 J.s), c is the speed of light (3.00 x 10^8 m/s), and λ is the wavelength of the light.

Plugging in the values given, we have E = (6.626 x 10^-34 J.s)(3.00 x 10^8 m/s)/(720.0 x 10^-9 m) = 2.76 x 10^-19 J/photon.

To find the energy in joules per mole of photons, we need to multiply by Avogadro's number, which is 6.022 x 10^23 photons/mol.

So the energy in joules/mol is (2.76 x 10^-19 J/photon)(6.022 x 10^23 photons/mol) = 1.66 x 10^5 J/mol = 1.661 x 10^15 J/mol.

Therefore, the best choice is C.

A Crystal Emits a Light of Wavelength 720