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

To solve the problem, we need to analyze the relationship between the terminal voltage \( V \) of a cell and the current \( I \) flowing through it when connected to a variable resistor \( R \). The cell has an electromotive force (emf) \( \epsilon \) and an internal resistance \( r \).

### Step-by-Step Solution:

1. **Understanding the Relationship**:
The terminal voltage \( V \) across the cell can be expressed as:
\[
V = \epsilon - I \cdot r
...