Ultraviolet light emits a total of 2.5 * 10^-17 J of light at a wavelength of 9.8 * 10^-7 m. How many photons does this correspond to?

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Physics

Nathanael

18 November, 17:36

Ultraviolet light emits a total of 2.5 * 10^-17 J of light at a wavelength of 9.8 * 10^-7 m. How many photons does this correspond to?

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Dax · Answer 1

Applying Planck's equation:

E = nhc/λ, with n = number of photons, h = Planck's constant, c = speed of light and λ = wavelength

2.5 x 10⁻¹⁷ = (6.63 x 10⁻³⁴) (3 x 10⁸) n / (9.8 x 10⁻⁷)

n = 123 photons