The ratio of the energy of a photon with $\lambda = 150\,nm$ to that with $\lambda = 300\,nm$ is

The rest mass of the photon is

Write equation of energy of photon.

Assertion : If the speed of charged particle increases both the mass as well as charge increases.
Reason : If $m_0 =$ rest mass and $m$ be mass at velocity $v$ then $m = \frac{{{m_0}}}{{\sqrt {1 – \frac{{{v^2}}}{{{c^2}}}} }}$ where $c =$ speed of light

Two metallic plates $A$ and $B$, each of area $5 ×10^{-4}m^2$ are placed parallel to each other at a separation of $1\ cm$. Plate $B$ carries a positive charge of $33.7 \,pc$. $A$ monochromatic beam of light, with photons of energy $5\, eV$ each, starts falling on plate $A$ at $t = 0$, so that $10^{16}$ photons fall on it per square meter per second. Assume that one photoelectron is emitted for every $10^{6}$ incident photons. Also assume that all the emitted photoelectrons are collected by plate $B$ and the work function of plate $A$ remains constant at the value $2\, eV$. Electric field between the plates at the end of $10$ seconds is