The work function for aluminum is $4\mathrm{.}08$ eV $.$ Ultraviolet light of wavelength $144$ nm is incident on the clean surface of a aluminum sample. We wish to predict the stopping voltage we will need for electrons ejected from the surface.

$($a$)$ What is the photon energy of the ultraviolet light?

eV

$($b$)$ How do you know that these photons will eject electrons from aluminum?

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$($c$)$ What is the maximum kinetic energy of the ejected photoelectrons?

eV

$($d$)$ What stopping voltage would be required to arrest the current of photoelectrons?

V