Electricity is one of the most fascinating and useful phenomena in science. From lighting up our homes to powering devices, it plays a vital role in our lives. To understand electricity better, one of the first concepts we learn is Ohm’s Law, a simple yet fundamental rule that connects voltage, current, and resistance.
This article explains Ohm’s Law, its mathematical expression, applications, and how we can verify it experimentally. Let’s dive in!
Ohm’s Law was discovered by Georg Simon Ohm, a German physicist, in 1827. It explains the relationship between the electric current flowing through a conductor and the voltage applied across it.
According to Ohm’s Law:
The current flowing through a conductor is directly proportional to the voltage applied across its ends, provided the temperature and other physical conditions remain constant.
In simple terms, if we increase the voltage, the current also increases, and if we decrease the voltage, the current decreases. The resistance of the conductor determines how much current flows for a given voltage.
The relationship between voltage (V), current (I), and resistance (R) is given by:
Where:
Ohm’s Law is valid under the following conditions:
Ohm’s Law can be verified through a simple experiment. Let’s go step by step to understand how it’s done.
Here’s how the circuit is set up:
Record your observations in a table like this:
| Voltage (V) | Current (I) | Resistance (R) |
| 1.5 | 0.3 | 5.0 |
| 3.0 | 0.6 | 5.0 |
| 4.5 | 0.9 | 5.0 |
If the resistance remains constant for all readings, it confirms that Ohm’s Law is valid for the given conductor.
Ohm’s Law is used in many practical applications, including:
Ohm’s Law has its limitations. It does not apply to:
Ohm's law states that the current flowing through a conductor is directly proportional to the voltage across it, provided the temperature remains constant.
To verify Ohm's law, set up a simple circuit with a battery, resistor, ammeter, and voltmeter. Measure the current and voltage at different points, and check if the V/I ratio remains constant.
The three formulas are V = I*R, I = V/R, and R = V/I, where V is voltage, I is current, and R is resistance.
The conclusion is that if the V/I ratio remains constant at different points in the circuit, Ohm's law is verified.
The objective is to confirm the relationship between voltage, current, and resistance as stated by Ohm's law in a real-world scenario.
When current flows through a conductor, electrons move through the material, which may generate heat.
It's called Ohm's law after the German scientist Georg Simon Ohm who first formulated it in 1827.
The symbol for ohms is the Greek letter omega (Ω).