Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of:

Which of the following contains the maximum number of atoms?

If in a regular polygon,the number of diagonals is $54$,then the number of sides of the polygon is:

If Avogadro number $N_A$ is changed from $6.022 \times 10^{23} \ mol^{-1}$ to $6.022 \times 10^{20} \ mol^{-1}$,this would change:

In the ground state,an element has $13$ electrons in the $M$ shell. The element is

$A$ sonometer wire resonates with a given tuning fork,forming standing waves with five antinodes between the two bridges when a mass of $9 \, kg$ is suspended from the wire. When this mass is replaced by a mass $M$,the wire resonates with the same tuning fork,forming three antinodes for the same positions of the bridges. The value of $M$ is .... $kg$.