The element with atomic number $12$ belongs to ......... group and ......... period.

The work function of a metallic surface is $5.01 \ eV$. The photo-electrons are emitted when light of wavelength $2000 \ \mathring{A}$ falls on it. The potential difference applied to stop the fastest photo-electrons is .............. $volts$ $[h = 4.14 \times 10^{-15} \ eV \cdot s]$

$A$ vessel contains a mixture of one mole of oxygen and two moles of nitrogen at $300 \ K$. The ratio of the average rotational kinetic energy per $O_2$ molecule to that per $N_2$ molecule is

The $IUPAC$ name of the given compound is

If $x = \sqrt{\frac{2+\sqrt{3}}{2-\sqrt{3}}}$,then $x^2(x-4)^2$ is equal to:

Two thin wire rings,each having a radius $R$,are placed at a distance $d$ apart with their axes coinciding. The charges on the two rings are $+q$ and $-q$. The potential difference between the centres of the two rings is