If power in external resistance $R$ is maximum then

$(i) R = r$                              $(ii)$ Power in $R$ is $\frac{{{E^2}}}{{4R}}$

$(iii)$ Input power $\frac{{{E^2}}}{{2R}}$         $(iv)$Efficiency is $50\%$

  • A$(i), (ii)$
  • B$(i), (iii)$
  • C$(i), (ii), (iii)$
  • D
    All
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d
If power in $\mathrm{R}$ is maximum then

$\boxed{R = r\,}\,i = \frac{E}{{2R}} = \frac{E}{{2r}}$

Power in $\mathrm{R}$

$P=\left(\frac{E}{2 R}\right)^{2} \cdot R=\frac{E^{2}}{4 R}$

input power.

$P_{\text {in }}=\left(\frac{E}{2 R}\right)^{2} \cdot 2 R=\frac{E^{2}}{2 R}$

Efficiency $=\frac{P_{\text {out }}}{P_{\text {in }}} \times 100=50 \%$

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