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## Homework Statement

How fast must an electron move to have a Kinetic Energy equal to the photon energy of sodium light at wavelength 590 nm.

## Homework Equations

photon energ E =hf

h = 6.63 * 10 ^ -34 J * s = 4.14 = 10^-15 eV *s

f = c/ lamda

c = 3 * 10^ 8 m/s

mass of an electron is 9.11 * 10 ^ -31 (kg) or 511 keV

## The Attempt at a Solution

Ok I solved for the energy of a photon for sodium light

E = 6.63 * 10 ^ -34 J *s * ( (3* 10 ^ 8 m/s) / 590 * 10 ^ -9 meters) = 1.989 * 10 ^ -25 Joules

Were solving for Velocity. How do I do this problem it's confusing.

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