Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Electrons and Photons, Exercise 2: Critical Thinking

The $I-V$ curve for a photocell is best represented by the figure.

If $V_1$ and $V_2$ are stopping potentials for incident photons of wavelengths ${\lambda }_1$ and ${\lambda }_2$ for same cathode material, then Planck's constant is given by $[e=$ charge on the electron, $c=$ speed of light]

Ultraviolet radiation of $9.2 \mathrm{eV}$ falls on an aluminium surface of work function $4.2 \mathrm{eV}$. The kinetic energy in $\mathrm{Joule}$, of the fastest electron emitted is approximately
 

Choose the graph showing the correct relationship between the stopping potential $V_0$ and the frequency $v$ of light for potassium and tungsten.

Two identical photo-cathodes receive the light of frequencies $\nu$ and $\frac{\nu }{2}.$ If the velocities of the photoelectrons (of mass $m$) coming out are respectively $v_1$ and $v_2$, then:-

The stopping potential $\left({\mathrm{V}}_0\right)$ versus frequency (v) plot of a substance is shown in figure. The threshold wavelength is

Assertion: If the maximum kinetic energy of electrons emitted by a photocell is $5 \mathrm{eV}$, then the stopping potential is $5 \mathrm{V}$.

Reason: Stopping potential for the fastest photoelectrons is numerically equal to their kinetic energy.

Assertion: From the graph above, it follows that the work function of metal $\mathrm{B}$ is greater than that of metal $\mathrm{A}$. Reason: The work function  depend upon the slope of the graph.