Question

Find the resistance of a conductor if 0.24 A current is passing through it and a potential difference of 24 V is applied across it.

Answer 1

Resistance: Resistance is a measure of the opposition to current flow in an electrical circuit, resistance is measured in ohms (Ω).
Potential difference: Potential difference is nothing but the voltage difference between any two points in a circuit and it is due to potential difference which makes current flow, potential difference does not move or flow it can only be applied. It is measured in volts (V).

Complete step by step solution:
Given:
Current $\left( I \right)\; = {\text{ }}0.24\;A$.
Potential differences $\left( V \right){\text{ }} = {\text{ }}24V$
To find: Resistance (R)
We know that from the ohm’s law:
$R = \dfrac{V}{I}$
$\therefore R = \dfrac{{24}}{{0.24}}$
$= \dfrac{{24x100}}{{24}}$
$R = 100\,\Omega$
Ohm’s law: Ohm’s law states that the voltage or potential difference between two points is directly proportional to the current or electricity passing through the resistance, and directly proportional to the resistance of the circuit.
$V \propto \,I$
$V = RI$
$I = \dfrac{V}{R}$
For pure metals the temperature coefficient is positive and resistance will increase with increase in temperature. Carbon, silicon and germanium are some of the elements whose temperature coefficient is negative which means resistance decreases with increase in temperature. There are some metal alloys whose temperature coefficient of resistance is very much close to zero, which means the resistance hardly changes when the temperature is varied.

Note: The Ohm's law is applied only at constant temperature because the resistance of any material varies with the change in temperature, and ohm's law is only valid for linear elements. It shows a linear relationship between the applied voltage and the resulting current, resistance being a constant.