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?

Energy of an electron and a photon are equal. If the wavelength of the electron is $1\,\mathring{A}$,then the wavelength of the photon is approximately ............. $\mathring{A}$.

In an experiment on the photoelectric effect,plates of three different metals $p, q,$ and $r$ are used,with work functions $\phi_p = 2.0\ eV$,$\phi_q = 2.5\ eV$,and $\phi_r = 3.0\ eV$,respectively. Three radiations of equal intensity with wavelengths $550\ nm, 450\ nm,$ and $350\ nm$ are incident on these plates. Which of the following $I \rightarrow V$ graphs is correct for the experimental results? $(hc = 1240\ eV\ nm)$

Dual nature of light is exhibited by

Match the following table.

$List-I$	$List-II$
$A$. Michelson-Morley experiment	$I$. The existence of anti-matter
$B$. Stern-Gerlach experiment	$II$. The existence of de-Broglie matter waves
$C$. Davisson-Germer experiment	$III$. Electrons have spins
$D$. Anderson discovery of positron	$IV$. The non-existence of ether

When a monochromatic point source of light is placed at $0.1\, m$ from a photocell,the cut-off voltage and saturation current are $0.8\, V$ and $24\, mA$ respectively. If the same source is placed at $0.2\, m$ away from the photocell,then the cut-off voltage and saturation current will be: