Question

What happens to the resistivity of a conductor if the temprature of conductor is increased
1. Increase 
2. Remains constant
3. Decrease
4. May decrease or increase

Answer 1

Correct Answer - Option 1 : Increase 

CONCEPT:

• The resistivities of metallic conductors within a limited range of temperature are given by the following equation

\(⇒\rho _{T} = \rho _{0}[1+α (T-T_{0})]\)

Here, ρ_T = resistivity at a temperature T, ρ₀ = resistivity at a reference temperature T₀, α = temperature coefficient of resistivity; the dimension of α is T^-1

• α is positive for conductors and negative for semiconductors.
• According to the above equation, a graph of ρT plotted against T would be a straight line i.e., the resistivity of a metallic conductor increases with increasing temperature.

EXPLANATION:

• As we discussed the conductor has a positive temperature coefficient, so from the above equation, it can be easily said that on increasing the temperature the resistivity of the conductor increases and vice versa is true. Hence, the correct option is (1).