Ohm's law states that the current flowing through a conductor between two points is directly proportional to the potential difference across the two points, and inversely proportional to the resistanc

Here are the solutions to the questions:

8.1.1

Ohm's law states that the current flowing through a conductor between two points is directly proportional to the potential difference across the two points, and inversely proportional to the resistance between them, provided the temperature and other physical conditions remain constant.

8.1.2

You need to draw a straight line of best fit through the plotted points on the graph. Ensure this line extends to cut both the potential difference (y-axis) and current (x-axis).

8.1.3

The terminal potential difference ($V$) is related to the EMF ($\mathcal{E}$), current ($I$), and internal resistance ($r$) by the equation $V = \mathcal{E} - Ir$.
When the current ($I$) is zero, the terminal potential difference ($V$) is equal to the EMF ($\mathcal{E}$).
From the graph, the y-intercept (where $I = 0 \, \text{A}$) is approximately $5.5 \, \text{V}$.
Therefore, the EMF of the battery is:

$$\mathcal{E} = \boxed{\text{5.5 V}}$$

8.1.4

The internal resistance ($r$) is the negative of the gradient of the potential difference versus current graph.
We will use two points from the line of best fit:
Point 1 (y-intercept): $(I_1, V_1) = (0 \, \text{A}, 5.5 \, \text{V})$
Point 2 (x-intercept, estimated): $(I_2, V_2) = (4.5 \, \text{A}, 0 \, \text{V})$