Almost all materials have resistance. Even the best conductor such as gold have some resistance. Common materials that have resistance are light, motors in the fan and heater
Resistance, R of a conductor is defined as the ratio of potential difference, V across the conductors to the current, I flowing through it
Therefore,
Where, R = resistance measured in ohm (Ω)
V = voltage measured in volt (V)
I = current measured in ampere (A)
Example of calculation on using the formula
1. When a potential difference of 12 V is applied across a conductor, it is found that the current passing through the conductor is 0.2 A. What is the resistance of the conductor?
[Answer : 60 Ω]
2. Voltage across a 250 Ω resistor is 15 V. What is the current flowing through the resistor?
[Amswer: 0.06 A]
3. What is the potential difference across a light bulb of resistance 5 Ω when the current that passes through is 0.5 A?
[Answer: 2.5 V]
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