Temperature dependence of resistance:
When temperature increases, the no. of collisions increases due to more internal energy and relaxation time decreases. Therefore, Resistance increases.
Temperature Coefficient of resistance:
If R2 < R1, then α is –ve.
R0 – Resistance at 0 ℃
R0 – Resistance at t ℃
R0 – Resistance at t1 ℃
R0 – Resistance at t2 ℃