A cell of emf ‘E’ and internal resistance ‘r’ is connected across a variable load resistor R. Draw the terminal voltage V versus (i) R and (ii) the current l.
It is found that when `R=4 Omega`, the current is 1 A and when R is increased to `9 Omega`, the current reduce to 0.5 A. Find the values of the emf E and internal resistance r.

Explanation

To solve the problem, we need to find the values of the emf \( E \) and internal resistance \( r \) of the cell based on the given conditions. Let's break down the solution step by step.

### Step 1: Understanding the Circuit
The terminal voltage \( V \) of a cell is given by the equation:
\[ V = E - I \cdot r \]
where:
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