A battery of emf 5V and internal resistance 2ohm is joined to a resistor of 8ohm. Calculate the terminal potential difference. ​

4V

Explanation:

First, we calculate the total resistance to the given battery cell of emf 5V. The total resistance is the sum of all the resistance in the cell i.e.

Total resistance = 2Ω + 8Ω = 10Ω

Using ohms law equation to calculate the current passing through the battery cell:

V = IR

Where; V = voltage, I = current, R = resistance

5V = I × 10Ω

I = 5/10

I = 0.5A

Terminal voltage is calculated by the us of the following equation:

V=emf−IR

Where; R is internal resistance

V = 5 - (0.5 × 2)

V = 5 - 1

V = 4V

Therefore, the potential difference across the terminals of the battery cell is 4V

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .