The energy needed for breaking a liquid drop of radius ' $R$ ' into 216 droplets, each of radius ' $r$ ' is ' $x$ ' times $T R^2$. The value of ' $x$ ' is [ $T=$ surface tension of the liquid].

Out of the following molecules the one which represents the polar molecule is

Six molecules of a gas in container have speeds $2 \mathrm{~m} / \mathrm{s}, 5 \mathrm{~m} / \mathrm{s}, 3 \mathrm{~m} / \mathrm{s}, 6 \mathrm{~m} / \mathrm{s}, 3 \mathrm{~m} / \mathrm{s}$, and $5 \mathrm{~m} / \mathrm{s}$. The r.m.s. speed is

If the power factor changes from 0.5 to 0.25 because impedance changes from $Z_1$ to $Z_2$ then $\mathrm{Z}_1=\mathrm{xZ}_2$. The value of x is (Resistance remains constant)