The internal resistance of a primary cell is $4\, ohm$. It generates a current of $0.2\, amp$ in an external resistance of $21\, ohm$. The rate at which chemical energy is consumed in providing the current is .............. $J/s$
A$0.42$
B$0.84$
C$5$
D$1$
Medium
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D$1$
d (d) $\frac{H}{t} = {i^2}R$. Here total $R = (21 + 4) = 25\,\,\Omega $
$ \Rightarrow $ Rate of energy consumed $ = 0.2 \times 0.2 \times 25$$ = \,1\,\,J/s$
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