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A material has a work function of 4.0 eV. The maximum wavelength of incident light that can just eject photoelectrons from it is closest to

1. 310 nm
2. 400 nm
3. 540 nm
4. 220 nm

Correct answer: 310 nm

Solution

The maximum wavelength of light that can eject photoelectrons is determined by the work function using the equation λ = (hc)/(φ), where h is Planck's constant and c is the speed of light. Given a work function of 4.0 eV, the calculation yields a wavelength of approximately 310 nm, which corresponds to the energy threshold needed to release electrons.

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