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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