`2A` cell having an emf `epsilon` and internal resistance `r` is connected across a variable external resistance `R`. As the resistance `R` is increased, the plot of potential difference `V` across `R` is given by

Options

A.
B.
C.
D.

Answer

C

Explanation

(c ) Here, `E = I (R + r) implies E = IR + Ir`
and `E = V + Ir`
`E = V + (Er)/(R + r)`
`V = E - (E)/(R + r) xx r = E [1 - (1)/(1 + R//r)]`
This equaiton represents option `(c )`.