Question

What happens to resistance of a conductor
1. When temperature is increased
2. When the length is double
3.when area of cross section is increased

Answer 1

1 Resistance increases with the increase in temperature
2 Resistance will increase
3 Resistance will decrease

Answer 2

Resistance: The tendency to stop the flow of current.

R=ml/Ane² τ

τ(relaxation time) value decreases with increase in temperature.

1. From the above formula of resistance, since τ decreases,value of R increases, With increase in temperature. [see graph]
___________________________________________________________

R=ρl/A

2. When length is doubled, Resistance also doubles.
    since, R ∝  l 

3. From the above formula:
    R ∝ 1/A
   So, when area of cross section is increased, Resistance decreases.