The number of electrons in the valence shell of the central atom of a molecule is $8$. The molecule is

For the given logic gate circuit, which of the following is the correct truth table?

The figure shows the variation of the gravitational acceleration $a_g$ of four planets with the radial distance $r$ from the centre of the planet for $r \geq$ radius of the planet. Plots $1$ and $2$ coincide for $r \geq R_2$,and plots $3$ and $4$ coincide for $r \geq R_4$. The sequence of the planets in the descending order of their densities is:

The experimentally determined molar mass of a non-volatile solute,$BaCl_2$,in water by Cottrell's method,is

If a change in current of $0.01 ~A$ in one coil produces a change in magnetic flux of $2 \times 10^{-2} ~Wb$ in the other coil,then the mutual inductance of the two coils in henry is (in $~H$)

Which of the following is a group of blue-green algae that acts as a biofertilizer?