Ohm's Law

Electricity is something we use every day. From switching on a light to charging a phone, electric current is always around us. But how does electricity work inside the wires? How do engineers and electricians know how much current flows in a circuit? The answer lies in a basic and very important rule in physics called Ohm’s Law.

Ohm’s Law explains the relationship between three things in an electric circuit—voltage, current, and resistance. It helps us understand how electricity flows and how different parts of a circuit affect that flow. The law is named after Georg Simon Ohm, a German scientist who discovered it in the 1800s.

Let’s take a simple example. Imagine water flowing through a pipe. The voltage is like the pressure pushing the water. The current is like the flow of water. The resistance is anything inside the pipe that slows the water down, like a narrow section or blockage. Ohm’s Law works in a similar way for electric circuits.

The formula for Ohm’s Law is:
V = I × R
Where:

• V is the voltage (in volts)
• I is the current (in amperes)
• R is the resistance (in ohms)

This means that if you know any two of the values, you can easily find the third. For example, if you know the voltage and resistance, you can calculate how much current will flow through the wire.

Ohm’s Law is very useful in real life. Electricians use it to check if a wire can safely carry current. Engineers use it to design circuits for things like televisions, fans, mobile chargers, and more. It also helps in solving problems when electrical devices are not working properly.

Do Check: Weathering

Even though Ohm’s Law is a simple formula, it is a powerful tool for learning and working with electricity. It is one of the first things taught in physics and electrical engineering because it builds the foundation for understanding how circuits behave.

In this article, we will learn more about what Ohm’s Law means, how to use its formula, solve simple problems, and explore where it is used in real-world situations.

What is Ohm’s Law?

Ohm’s Law states that the current (I) passing through a conductor is proportional to the applied voltage (V) and is inversely proportional to its resistance (R).

Formula:V = I × R

• V = Voltage (Volts, V)
• I = Current (Amperes, A)
• R = Resistance (Ohms, Ω)

Ohm’s Law Calculations

1. Calculating Voltage, Current, and Resistance

• Voltage: V = I × R
• Current: I = V / R
• Resistance: R = V / I

2. Example Calculations

Example 1: Finding Current

A 12 V battery is connected to a 4 Ω resistor:

I = V / R = 12 V / 4 Ω = 3 A

Example 2: Finding Resistance

If a 9 V battery creates 3 A of current:

R = V / I = 9 V / 3 A = 3 Ω

Do Check: Tension

Ohm’s Law in Hindi (ओम का नियम)

For students who prefer learning in Hindi, here’s ohm's law in Hindi:

Ohm’s Law Hindi Definition (ओम का नियम परिभाषा)

“यदि तापमान और अन्य भौतिक दशाएँ स्थिर रहती हैं, तो किसी चालक से प्रवाहित विद्युत धारा उस पर लगाए गए विभवांतर के समानुपाती होती है।”

ओम का नियम सूत्र (Formula):
V = I × R

Where:

• V = विभवांतर (Voltage)
• I = धारा (Current)
• R = प्रतिरोध (Resistance)

Applications of Ohm’s Law

Limitations of Ohm’s Law

Not all materials follow Ohm’s Law. Here are the limitations of ohm's law:

1. Non-Ohmic Materials: Semiconductors, vacuum tubes, and diodes do not follow this law.
2. Temperature Changes: Resistance can change if the material heats up.
3. High Frequency Circuits: AC circuits also include capacitive and inductive reactance.
4. Electrolytes and Gases: These materials behave differently under voltage.

So, ohm’s law is most accurate for metallic conductors under constant temperature.

Conclusion

Ohm’s Law is one of the most important and easiest concepts in physics. Whether you're in Class 10, Class 12, or just curious about how electricity works, understanding ohm's law gives you the power to solve real-world problems.

It explains how voltage, current, and resistance work together in any electrical circuit. You’ve now learned how to state and explain ohm’s law, use the ohm’s law formula, draw the ohm’s law diagram, and understand the ohm’s law graph.

So next time you flip a switch or charge your phone—remember, Ohm’s Law is working behind the scenes!