Which of the following methods is used to obtain pure water from seawater?

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:

The differential equation of the family of parabolas with focus at the origin and the $x$-axis as axis is

In a Young's double-slit experiment,the fringe width is $0.2 \, mm$. If the wavelength of light used is increased by $10\%$ and the separation between the slits is also increased by $10\%$,the fringe width will be.......$mm$.

$A$ metal rod of length '$l$' rotates about one of its ends in a plane perpendicular to a magnetic field of induction '$B$'. If the e.m.f. induced between the ends of the rod is '$e$',then the number of revolutions made by the rod per second is

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