Resistance of a Conductor

Table of Contents

• Factors Influencing the Resistance of a Conductor
• Summary
• What’s Next?

In the previous segment, we have understood the concept of Ohm’s Law. In this segment, we will study the resistance of a conductor.

What are the Factors influencing the resistance of a conductor?

• The resistance of a conductor depends on different factors. To understand them, let’s perform a simple experiment using an electrical circuit with a plug key, a power source and an ammeter.

Experimental setup

• Connect a nichrome wire of length ‘l’ to the circuit. Then plug the key and measure the

reading in the ammeter.

Case 1

Case	Factors	Current
1	Length l	I₁

• In the next case, double the length of the nichrome wire keeping its thickness the same. Now measure the current. You will notice that the current measured is half of the current measured initially. So when the length was doubled, the current halved.

Case 2

Case	Factors	Current
1	Length l	I₁
2	Length 2l	I₁/2

• In the third case, replace the nichrome wire with a thicker one, but with the same

length ‘l’. By doing so we have increased the cross-sectional area ‘A’ of the wire. Now on

measuring the current, you will notice that it’s more than the original current ‘I₁’.