Question

If we add impurities in semiconductor than the number of electrons in conduction band increase is this imply that the semiconductor with impurities will conduct more electricity? Or the electricity remains same?

Answer 1

Electricity is a flow of charge or we can say it is a current andcurrent will increase when you add impurity.

Here is the explanation

If you increase impurity level than number of free electron will increase which will increase the conductivity of the semiconductor.
Conductivity of the semiconductor σ =n*e* μ where n is the number of electron, e is the charge of electron

and μ is the mobility of electron.

σ =1/ρ And Resistance is directly proportional to ρ

So when we increase impurity level it will increase electron concentration which will increase conductivity hence decrease resistivity as well as resistance.

So for same supply voltage highly doped semiconductor will produce large current because of less resistance compared to less doped or less impurity semiconductor.