The graph between the stopping potential ( $V_0$ ) and $(1 / \lambda)$ is shown in the figure $\phi_

Question

The graph between the stopping potential ( $V_0$ ) and $(1 / \lambda)$ is shown in the figure $\phi_1, \phi_2$ and $\phi_3$ are work functions. Which of the following is correct?

Professor PC Thomas Classes · Answer

(a) : For incident wavelength $\lambda$, threshold wavelength $\lambda_0$ and stopping potential $V_0$, using Einstein's photoelectric equation. $$ \frac{h c}{\lambda}-\phi=e V_0 ; \quad V_0=\frac{h c}{e \lambda}-\frac{\phi}{e} $$ Here, slope $=\frac{h c}{e}=	an 	heta$ At $V_0=0 \mathrm{~V}, \phi=\frac{h c}{\lambda} \quad$ or $\quad \phi \propto \frac{1}{\lambda}$ Hence, $\phi_1: \phi_2: \phi_3=\frac{1}{\lambda_1}: \frac{1}{\lambda_2}: \frac{1}{\lambda_3}=1: 2: 4$