What is the energy in eV of a photon with the wavelength of Lyman Lα at 121.5 nm in the ultraviolet range? A)1030 eV B)1.51 × 10^-4 eV C)1.02 × 10^-8 eV D)10.2 eV

Question

Quizplus · Accepted Answer

The energy E of a photon is given by E = hc/λ, where h is Planck's constant (6.626 x 10^-34 J s), c is the speed of light (2.998 x 10^8 m/s), and λ is the wavelength of the photon. Converting the given wavelength of 121.5 nm to meters gives λ = 1.215 x 10^-7 m. Plugging in these values, we get E = (6.626 x 10^-34 J s)(2.998 x 10^8 m/s)/(1.215 x 10^-7 m) = 1.637 x 10^-18 J. To convert this energy to eV, we divide by the elementary charge e (1.602 x 10^-19 C) and get E = 10.2 eV. Therefore, the correct answer is D.

What Is the Energy in EV of a Photon with the Wavelength