Explain the working of photo emissive cell. Write any two applications of photoelectric cells.

 

A diffraction pattern is obtained using a beam of red light.What happens if the red light is replaced by blue light ?

A plano-convex lens of radius $3 \mathrm{m}$ is placed on an optically flat glass plate and is illuminated by monochromatic light. The radius of the $8^{\mathrm{th}}$ dark ring is $3.6 \mathrm{mm}$. Calculate the wavelength of light used.

Derive Einstein's photoelectric equation.

The threshold frequency of a photo-sensitive surface is $5\times {10}^{14} \mathrm{Hz}$. Then which of the following can produce photoelectric emission from the same surface?

The De-Broglie wavelength of a neutron of kinetic energy $\mathrm{K}$ is $\mathrm{\lambda }$. When its kinetic energy is $4 \mathrm{K}$, what is the De-Broglie wavelength of the neutrons?

Explain the working of photo emissive cell. Write any two applications of photoelectric cells.