QUESTIONS

A retarding potential of $0.5 V$ is required to block the movement of electrons from the cathode of a photoelectric cell when violet light of wavelength $4000 \stackrel{\mathrm{o}}{A}$ strikes its surface. Find the threshold frequency.

A retarding potential of $0.5 V$ is required to block the movement of electrons from the cathode of a photoelectric cell when violet light of wavelength $4000 \stackrel{\mathrm{o}}{A}$ strikes its surface. Find the energy light of wavelength $3000 \stackrel{\mathrm{o}}{A}$.

A retarding potential of $0.5 V$ is required to block the movement of electrons from the cathode of a photoelectric cell when violet light of wavelength $4000 \stackrel{\mathrm{o}}{A}$ strikes its surface. Find the maximum energy of the electron emitted from the cathode surface when $3000 \stackrel{\mathrm{o}}{A}$ light strikes it.

Find the frequency of light which ejects from a metal surface electrons which are fully stopped by a retarding potential of $3 V$. The photoelectric effect starts in this metal at a frequency of  $6\times {10}^{14} {\mathrm{s}}^{-1}\left(h=6.63\times {10}^{-34} \mathrm{Js}, \mathrm{e}=1.6\times {10}^{-19} \mathrm{C}\right)$.

Ultraviolet light of wavelength $800 \stackrel{\mathrm{o}}{A}$ and $700 \stackrel{\mathrm{o}}{A}$, when allowed to fall on hydrogen atoms in their ground state, is found to liberate electrons with kinetic energies $1.8 eV$ and $4.0 eV$ respectively. Find the value of Planck's cosntant.

In an experiment of photoelectric effect, the graph of maximum kinetic energy $E_k$ of the emitted photoelectrons versus the frequency $v$ of the incident light is a straight line shown in the figure. Calculate threshold frequency.

In an experiment of photoelectric effect, the graph of maximum kinetic energy $E_k$ of the emitted photoelectrons versus the frequency $v$ of the incident light is a straight line shown in the figure. Calculate work function $W$ of cathode-metal in $eV$.

In an experiment of photoelectric effect, the graph of maximum kinetic energy $E_k$ of the emitted photoelectrons versus the frequency $v$ of the incident light is a straight line shown in the figure. Calculate stopping potential for the electrons emitted by light of frequency $v=30\times {10}^{14} {\mathrm{s}}^{-1}$.