Question

A cell of emf 18v has an internal resistance of 3ohm . the terminal p.d of the battery becomes 15v when connected by a wire. find the resistance of the wire.​

Answer 1

Resistance = 15 Ohms

Step-by-step explanation:

Given the following data;

Emf voltage = 18 V

Internal resistance = 3 Ohms

Potential difference = 15V

To find the resistance of the wire;

First of all, we would determine the current flowing through the wire.

Mathematically, the terminal potential difference is given by the formula;

V = E - IR

Where;

V is the terminal potential difference.

E is the electromotive force (emf).

I is the current.

R is the internal resistance.

15 = 18 - I*3

15 = 18 - 3I

3I = 18 - 15

3I = 3

I = 1 Amperes

Next, we find the resistance of the wire;

Voltage = current * resistance

Substituting into the formula, we have;

15 = 1 * resistance

Resistance = 15/1

Resistance = 15 Ohms