Q. Choose the only false statement from the following :
A) Substances with energy gap of the order of 10 eV are insulators
B) The conductivity of a semiconductor increases with increases in temperature
C) In conductors the valence and conduction bands may overlap
D) The resistivity of a semiconductor increases with increase in temperature
Explanation
[Solution from source] In a semiconductor more electrons cross the band gap as temperature rises, so conductivity increases and resistivity decreases. The statement that resistivity increases with temperature is therefore the false one; the other three are true. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.