Question

On what factors does resistance of a conductor depend? Describe an experiment to study the factor on which the resistance of a conducting wire depends.

Answer 1

Answer :-

Resistance :- The property of a material to resist the flow of electric current through itself is called resistance.

Resistance of a conductors depends upon the following factors :-

• Length of the conductor.

As the length increases the resistance of conductor will also increases.

• Cross section area of the conductor.

When area of cross section is increased the resistance of the conductor decreases.

• Temperature of the conductor.

Resistance increases with increase in temperature of the conductor.

• Nature of the material.

Resistance also depends upon the nature of the material of the conductor.

From this we concluded the formula of resistance given by :-

$\boxed{\sf{R = p \dfrac{l}{a}}}$

Experiment to show that the resistance of a conductor depends on above mentioned factors.

Aim :-

To show that the resistance of a conductor depends on its length and area of cross section.

Material required :-

Wire of different length and different cross section area, battery,

key , voltmeter, ammeter etc.

Procedure:-

First make a closed circuit by connecting battery and key.

Now take a point A and B and insert different lengths of wire and carefully measure the reading of voltmeter and ammeter.

By using the ohms law R = V/I

Make an observation table for the following observations Now, connect the wire of different area of cross sections.

Observation :-

You will find that more the length of wire more its resistance.

And, more the area of cross section less its resistance.

Conclusions :-

• Length is directly proportional to resistance of wire.

• Area is inversely proportional to resistance of wire.

Answer 2

Answer:

The resistance of a conductor depends directly on its length, inversely on it's area of cross section, and also on the material of the condutor.