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Problem 7 - Entrance Test

A photon has an energy of 3.0 eV. What is its wavelength?

Correct: A

E = hc/λ, so λ = hc/E. Using h = 4.14 x 10⁻¹⁵ eV s and c = 3 x 10⁸ m/s, λ = (4.14 x 10⁻¹⁵ eV s * 3 x 10⁸ m/s) / 3.0 eV = 4.14 x 10⁻⁷ m = 414 nm.