Which one of the following reactions occurs at the anode in the Castner process of extracting sodium metal?

With what minimum velocity should a block of mass $m$ be projected from the left end $A$ towards end $B$ such that it reaches the other end $B$ of a conveyor belt of length $L$ moving with a constant velocity $v$ in the opposite direction? The friction coefficient between the block and the belt is $\mu$.

When two species of different genealogy come to resemble each other as a result of adaptation,the phenomenon is termed as

The ratio of the lengths of two wires $A$ and $B$ of the same material is $1 : 2$ and the ratio of their diameters is $2 : 1$. If they are stretched by the same force,then the ratio of the increase in their lengths will be:

The equation of the circle whose diameter is the common chord of the circles $x^2+y^2+2x+3y+2=0$ and $x^2+y^2+2x-3y-4=0$ is

The locus of a point such that the sum of its distances from the points $(0, 2)$ and $(0, -2)$ is $6$,is