In the given figure,the potential difference between $A$ and $B$ is ............ $V$.

$A$ particle executes simple harmonic oscillation with an amplitude $a$. The period of oscillation is $T$. The minimum time taken by the particle to travel half of the amplitude from the equilibrium position is

Two oxides of nitrogen,$NO$ and $NO_2$,react together at $253 \ K$ to form a compound of nitrogen $X$. $X$ reacts with water to yield another compound of nitrogen $Y$. The shape of the anion of $Y$ molecule is:

$ATP$ase enzyme needed for muscle contraction is located in

Sporeine was developed in

The area (in sq units) bounded by the curves $y^2=4x$ and $x^2=4y$ is