Question

for which substance among the following conductivity increase with temperature -copper, germanium, silver,, iron

Answer 1

Out of those four metals, iron conductivity is increase with the increase of temperature because it is the good conductor of temperature and as it is the good conductor of temperature it’s conductivity is also increasing with the increase of temperature.

So the logic is increase the temperature you can then increase the conductivity of iron also.

Answer 2

Thermal conductivity: Thermal conductivity is the ability to conduct heat energy.

The thermal conductivity of the metals decreases with the increase in temperature as the no of free electrons increases.

When iron is heated, initially, the thermal conductivity reduces as the free electrons expand. But, upon continuous heating, the thermal conductivity of iron increases.

Hence, iron is the answer.