# Plz solve this and explain it in detail.

Solution,
For the parallel combination of cells, effective emf is E and effective internal resistance is $\frac{r×r}{r+r}=\frac{r}{2}$.
This combination is in series with another cell of emf E and internal resistance, r.
Thus, the net emf of this mixed combination of 3 cells, Eo = E + E = 2E.
and
the equivalent internal resistance of this mixed combination of cells, ${r}_{o}=\frac{r}{2}+r=\frac{3r}{2}$
Thus, current across the load R is
$i=\frac{{E}_{o}}{{r}_{o}+R}=\frac{2E}{R+3r}{2}}=\frac{4E}{2R+3r}$
Power dissipated by the resistor,

Thus,
Ans (3)

• 0
What are you looking for?