How much mas:'; is converted into energy per day in Tarapur nuclear power plant operated at 10⁷ kW'? 

Here,  P = 10⁷kW  =  10¹⁰  W = 10¹⁰$j{s}^{-1}$
Time, t = 1 day = 24 x 60 x 60 s
Energy produced per day,
E = Pt = 10¹⁰ x 24 x 60 X 60 = 864 X 10¹² J
As, E = mc²

$\Rightarrow \text{ Mass, }m=\frac{E}{c^2}=\frac{864\times {10}^{12} \mathrm{J}}{{\left(3\times {10}^8\right)}^2{ \mathrm{ms}}^{-1}}$

                     $=9.6\times {10}^{-3} \mathrm{kg}=9.6 \mathrm{g}$