Ohm’s Law

Ohm’s law establishes a connection between current and potential differences. At constant temperature, the current flowing through a conductor is precisely proportional to the potential difference across its ends, according to Ohm’s law. If I denotes the current flowing through a conductor and V denotes the potential difference (or voltage) at its ends, then Ohm’s law states:

I ∝ V (At constant temp.)

⇒ V ∝  I

⇒ V = R × I

Where R is the conductor’s “resistance” constant. The value of this constant is determined by the conductor’s type, length, cross-sectional area, and temperature. The equation above can also be written as:

Where,

• V is the Potential difference,
• I is the Current, and
• R is the Resistance (which is a constant).

Example: Potential difference between two points of a wire carrying a 2 ampere current is 0.1 volt. Calculate the resistance between these points.

Solution:

According to the OHM Law, V = R × I

⇒ 0.1 = R × 2

⇒ R = 0.1 / 2

⇒ R = 0.05 ohm

Graph Between V and I

If a straight line is made between the potential difference readings (V) and the related current values (I), the graph is determined to be a straight line flowing through the origin. Only when the two quantities are directly proportionate to one another can a straight-line graph be produced. We get the conclusion that current is exactly proportional to the potential difference because the “current potential difference” graph is a straight line. Graph OA clearly shows that the current I increases along with the potential difference V as V increases, but the ratio of V/I does not change. Resistance of the conductor is the name of this constant.

Resistance of a Conductor

Resistance is the quality of a conductor that causes it to resist the flow of current through it. A conductor’s resistance is equal to the potential difference between its ends divided by the current flowing through it.

Where,

• V is the Potential difference,
• I is the Current, and
• R is the Resistance.

The resistance of a conductor is determined by its length, thickness, material, and temperature. The ohm is the SI unit of resistance, represented by the symbol omega, Ω.

NCERT Notes for Class 10 Physics Chapter 12 Electricity is important to study this chapter carefully because it forms the foundation for many other concepts that you will learn later on. Many exam questions will be based on this chapter, so it is essential to have a good understanding of the material.

Chapter 12 of the NCERT Class 10 Physics textbook explores electricity. It covers a variety of topics, including electric current, circuits, power, resistance in series and parallel, and Ohm’s Law. These notes are designed to provide students with a comprehensive summary of the entire chapter and include all of the essential topics, formulas, and concepts necessary for success on exams.