Final answer:
To determine the work function of a metal in a photoelectric experiment, the increase in kinetic energy of photoelectrons as a result of increased photon energy is analyzed. The work function is calculated by using the relation KE = hf - φ, leading to a value of 1.0 eV.
Step-by-step explanation:
The student asked about the work function of a metal surface in the context of the photoelectric effect. When the energy of incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increases from 0.5 eV to 0.8 eV.
The increase in kinetic energy is due to the extra energy provided by incident photons. We can calculate the work function (φ) of the metal using the photoelectric equation KE = hf - φ, where KE is the kinetic energy, hf is the energy of the incident photon, and φ is the work function.
Given that the original kinetic energy of the electrons is 0.5 eV and increases to 0.8 eV, this means the initial energy of the photon is 0.5 eV + φ, and after a 20% increase, the energy of the photon is 0.8 eV + φ. Since a 20% increase corresponds to a factor of 1.2, we have (0.5 eV + φ) * 1.2 = 0.8 eV + φ, and by solving this equation, we can find the work function, which is 1.0 eV (Option B).