Q 12-03-019NEETNEET 2020Top questionEasy
The solids which have the negative temperature coefficient of resistance are :
Answer: (D) insulators and semiconductors
In semiconductors and insulators, heating frees more charge carriers across the band gap, so the resistance falls as the temperature rises: a negative temperature coefficient.
In metals, the carrier number is fixed and more collisions at higher temperature raise the resistance: a positive coefficient.
Solution by Sreeraj P, M.Sc Physics