The photoelectric work function of a particular target metal surface is accurately measured to be $3

Question

The photoelectric work function of a particular target metal surface is accurately measured to be $3.31 \mathrm{~eV}$. The absolute maximum threshold wavelength ($\lambda_0$) capable of successfully ejecting photoelectrons from this metal is approximately (Use $hc \approx 1240 \mathrm{~eV \cdot nm}$)

Professor PC Thomas Classes · Answer

(a) : The work function ($W_0$) defines the minimum threshold energy required to forcibly eject a bound electron. This energy equates directly to the threshold wavelength ($\lambda_0$) via the Planck relation $W_0 = \frac{hc}{\lambda_0}$. By isolating the wavelength, we obtain $\lambda_0 = \frac{hc}{W_0}$. Implementing the provided approximation $hc \approx 1240 \mathrm{~eV \cdot nm}$, the calculation yields $\lambda_0 = \frac{1240 \mathrm{~eV \cdot nm}}{3.31 \mathrm{~eV}} \approx 374.6 \mathrm{~nm}$, which rounds closely to $375 \mathrm{~nm}$.