When light of wavelength 350 nm is incident on a metal surface,the stopping potential of the photoelectrons is measured to be 0.500 V.What is the work function of this metal? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s,1 eV = 1.60 × 10^-19 J)

Question

Quizplus · Accepted Answer

The work function ($\phi$) can be calculated using the photoelectric equation: $E = \phi + KE$, where $E$ is the energy of the incident photons and $KE$ is the kinetic energy of the emitted electrons. The energy of the incident photons can be calculated using $E = \frac{hc}{\lambda}$, and the kinetic energy of the electrons is given by $KE = eV$, where $e$ is the charge of an electron (1.60 × 10^-19 C) and $V$ is the stopping potential. Substituting the given values: $E = \frac{6.626 \times 10^{-34} \times 3.00 \times 10^8}{350 \times 10^{-9}} = 5.66 \times 10^{-19} J = 3.54 eV$ (using $1 eV = 1.60 \times 10^{-19} J$ for conversion). The kinetic energy of the electrons is $KE = 0.500 eV$. Therefore, the work function is $\phi = E - KE = 3.54 eV - 0.500 eV = 3.04 eV$, which rounds to approximately 3.05 eV, making option B correct.

When Light of Wavelength 350 Nm Is Incident on a Metal