Ohm’s Law states that the electric current flowing through a conductor is directly proportional to the potential difference across its ends, provided the temperature remains constant. It was given by Georg Simon Ohm and is a fundamental law of electricity.
Verification of Ohm’s Law
Ohm’s law is verified using a circuit with a resistor, ammeter, and voltmeter. By changing the number of cells, different values of voltage and current are obtained. The ratio V/I remains constant, showing resistance is constant. A straight-line V–I graph confirms Ohm’s law.
Resistance
Resistance is the property of a material that opposes the flow of electric current.
- SI unit: ohm (Ω)
- Depends on: length, area of cross-section, material, and temperature
Applications of Ohm’s Law
- To calculate current, voltage, and resistance in circuits
- To determine power consumption and efficiency
- Used in designing electrical and electronic devices
- Applicable to linear conductors at constant temperature
Limitations (Failures)
- Not applicable to diodes, transistors, and non-linear devices
- Fails when temperature changes
- Not valid for non-ohmic materials