Q. Assertion The value of temperature coefficient of resistance is positive is for metals.
Reason The temperature coefficient of resistance for insulator is also positive.

 4493  209 AIIMSAIIMS 2011 Report Error

Solution:

On increasing the temperature of metals, the resistance of metals increases. Therefore temperature coefficient of resistance of metals is positive.
On increasing the temperature of insulators, the resistance decreases. Therefore, temperature coefficient of resistance of insulator is negative.