Question

The minimum frequency of light needed to eject electrons from a metal is called the threshold frequency, ν0. Find the minimum energy needed to eject electrons from a metal with a threshold frequency of 4.88 × 1014 s–1. With what kinetic energy will electrons be ejected when this metal is exposed to light with a wavelength of λ = 255 nm?

Answer 1

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Answer 2

Find the "excess" energy the photon provides to the electron: \(KE=\dfrac{hc}{\lambda}-\phi_0\)

The energy of the threshold, \(\phi_0\), is found with the frequency, \(\nu\):

\(KE=\dfrac{hc}{\lambda}-h\nu=h(\dfrac{c}{\lambda}-\nu)\)