The anode voltage of a photocell is kept constant. The wavelength of the incident light on the cathode is changed gradually. Then,the photoelectric current $I$ of the photocell varies according to which of the following graphs?

Unification of weak and electromagnetic interactions was done by

When a light source of power $P$ emitting monochromatic light of wavelength $\lambda$ is kept at a distance $r$ from a photosensitive surface of work function $\phi$ and surface area $A$,which of the following is the wrong option?

The de Broglie wavelength of a particle moving with a speed of $0.8 c$ is equal to the wavelength of a photon. If $c$ is the speed of light in vacuum, the ratio of the energy of the photon to the kinetic energy of the particle is:

$A$ radiation of $3.8 eV$ falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of $2 \times 10^{-4} T$. If the radius of the largest circular path followed by these electrons is $30 mm$,then the work function of the metal is (Mass of electron $m_{e} = 9 \times 10^{-31} kg$) (in $eV$)

Some laws/processes are given in Column $I$. Match these with the physical phenomena given in Column $II$.

Column $I$	Column $II$
$(A)$ Transition between two atomic energy levels	$(p)$ Characteristic $X$-rays
$(B)$ Electron emission from a material	$(q)$ Photoelectric effect
$(C)$ Mosley's law	$(r)$ Hydrogen spectrum
$(D)$ Change of photon energy into kinetic energy of electrons	$(s)$ $\beta$-decay