What is threshold frequency for photoelectric emission? Write down Einstein's photoelectric equation with the explanation of the symbols.

Draw a graph showing the variation of stopping potential with frequency of incident radiation for two photosensitive materials having work functions ${\mathrm{W}}_1$ and ${\mathrm{W}}_2\left({\mathrm{W}}_1>{\mathrm{W}}_2\right)$. Write two important conclusions that can be drawn from the study of these plots.

When a given photosensitive material is irradiated with light of frequency v, the maximum speed of the emitted photoelectrons equals ${\mathrm{V}}_{\max }$. The square of ${\mathrm{V}}_{\max }$ i.e., ${\overrightarrow{V}}^2$ is observed to vary with v, as per the graph shown in Fig.$19.12$. Obtain expression for (i) Planck's constant,

When a given photosensitive material is irradiated with light of frequency v, the maximum speed of the emitted photoelectrons equals ${\mathrm{V}}_{\max }$. The square of ${\mathrm{V}}_{\max }$ i.e., ${\overrightarrow{V}}^2$ is observed to vary with v, as per the graph shown in Fig.$19.12$. Obtain expression for work function of the given photosensitive material in terms of the parameters l, n and the mass m of the electron.

Fig. $19.13$ shows the variation of stopping potential ${\mathrm{V}}_0$ with the frequency v of the incident radiation for two photosensitive metals $\mathrm{X}$ and $\mathrm{Y}$. 

Which of the metals has a larger threshold wavelength? Give reasons.

Fig. $19.13$ shows the variation of stopping potential ${\mathrm{V}}_0$ with the frequency v of the incident radiation for two photosensitive metals $\mathrm{X}$ and $\mathrm{Y}$. 

Explain giving reasons, which metal gives out electrons, having larger kinetic energy, for the same wavelength of incident radiation

Fig. $19.13$ shows the variation of stopping potential ${\mathrm{V}}_0$ with the frequency v of the incident radiation for two photosensitive metals $\mathrm{X}$ and $\mathrm{Y}$. 

If the distance between the light source and metal X is halved, how will the kinetic energy of electrons emitted change? Give reason.