To determine the wavelength of a photon, you can use the equation:
λ = hc/E
where λ is the wavelength, h is Planck's constant (approximately 6.626 x 10^-34 J·s), c is the speed of light in a vacuum (approximately 2.998 x 10^8 m/s), and E is the energy of the photon.
Given that the energy of the photon is 2 eV, we need to convert it to joules. Since 1 eV is equal to 1.602 x 10^-19 J, we can calculate:
E = 2 eV × (1.602 x 10^-19 J/eV) = 3.204 x 10^-19 J
Now, we can substitute the values into the equation to find the wavelength:
λ = (6.626 x 10^-34 J·s × 2.998 x 10^8 m/s) / (3.204 x 10^-19 J)
Simplifying the expression:
λ = 6.211 x 10^-7 m
Therefore, the wavelength of a photon with an energy of 2 eV is approximately 621.1 nanometers (nm).