Question

Answer the following question.
A cell of emf E and internal resistance r is connected across a variable resistor R. Plot the shape of graphs showing a variation of terminal voltage V with (i) R and (ii) circuit current I.

Answer 1

Terminal Voltage V can be related to R by the following relation:

(i) `V = (ER)/(R+r)`

⇒ `V = (E)/(1+r/R)`

(ii) Terminal Voltage V can be related to I by the following relation: 

V = E - IR