A cell of emf `epsilon` and internal resistance r is connected across a variable resistor R. Plot a graph showing variation of terminal voltage V of the cell versus the current I. Using the plot, show how the emf of the cell and its internal resistance can be determined.

Explanation

The graphical relationship between voltage across R and the resistance R is given below When the cell of emf E and internal resistance `r` is connected across an external resistance R. the relation ship between voltage across R is given by
`[V=(E)/(1+(r)/(R))]` with increase of `R` v approaches closer to `E` and when `E` is infinite V reduces to `O`