Question

If we add impurity to a metal those atoms also deflect electrons. Therefore,

• A. The electrical and thermal conductivities both increase
• B. The electrical and thermal conductivities both decrease
• C. The electrical conductivity increases but thermal conductivity decreases
• D. The electrical conductivity decrease but thermal conductivity increases

Answer 1

The correct option is B The electrical and thermal conductivities both decrease

If the number of electrons increase, their number of collision, increasing the thermal and electrical resistance.
So, electrical and thermal conductivities both decrease.