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If the energy of the incident light is raised by 20%, the maximum kinetic energy of photoelectrons from a metal changes from 0.5 eV to 0.8 eV. What is the metal’s work function?

1. 0.65 eV
2. 1.0 eV
3. 1.3 eV
4. 1.5 eV

Correct answer: 1.0 eV

Solution

The work function of the metal can be determined using the photoelectric equation, which states that the maximum kinetic energy of photoelectrons is equal to the energy of the incident light minus the work function. Given that a 20% increase in energy raises the kinetic energy from 0.5 eV to 0.8 eV, we can calculate the work function as the difference between the initial energy and the maximum kinetic energy, leading to a work function of 1.0 eV.

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