Question

elements having positive and negative temp. coefficient of resis

Answer 1

Pure metals typically have positive temperature coefficients of resistance. ... A negative coefficient for a material means that its resistance decreases with an increase in temperature. Semiconductor materials (carbon, silicon, germanium) typically have negative temperature coefficients of resistance.

Answer 2

Hey guys

here is your answer :-


__________________________
_____________________________

⚡The extent and rate of oxidation and wear are mainly dependent on microstructure and/or composition of the surfaces concerned. Therefore, resistance to oxidation and wear may be imparted or improved primarily by suitable modification of the microstructure and/or composition of the near-surface region. 


---------------------------------
ok it helps you ✌✌✌
----------------------------------