Given: Plank's constant h = 6.626 x 10⁻³⁴ J.s
Speed of light c = 2.998 x 10⁸ m/s
Wavelength λ = 500 nm convert to meter = 5 x 10⁻⁷ m
Required: Energy E =?
Formula: E = hc/λ
E = (6.626 X 10⁻³⁴ J.s)(2.998 X 10⁸ m/s)/5 x 10⁻⁷ m
E = 3.97 X 10⁻¹⁹ J or in termS of electron volt
E = 2.48 eV