The stored energy, of a capacitor charged to $100 \mathrm{~V}$, is 1 J. capacitor is (a) $2 \times 10^{4} \mathrm{~F}$ (b) $2 \times 10^{4} \mathrm{~F}$ (c) $2 \times 10^{2} \mathrm{~F}$ (d) $1.6 \times 10^{19} \mathrm{~F}$