(a) A cell of emf `E` and internal resistance `r` is connected to a resistance `R`.
(i) Relate `r` and `R`, so that power in `R` is maximum.
(ii) Maximum power consumed by `R`.
(iii) Efficiency.
(b) Find value `r` in terms of `R` so that power in external circuit is maximum.

(c) A battery of internal resistance `4Omega` is connected to the network of resistance as shown in the figure. what must be the value of `R` so that maximum power is delivered to the network? what is tha maximum power?