An object made of materials like silicon; conductivity increases with temperature; sits between a metal and an insulator

• A. Conductor
• B. Insulator
• C. Semiconductor
• D. Alloy

Answer: (C)

The key idea is how temperature affects electrical conductivity. Metals conduct well, but their conductivity tends to decrease as temperature rises because lattice vibrations scatter electrons more. Insulators conduct poorly, and heating doesn’t suddenly make them conduct well at normal temperatures. Silicon-type materials, however, are semiconductors: as temperature increases, more electrons gain enough energy to cross the band gap and become charge carriers, so conductivity increases. This explains why the described object—made of materials like silicon and showing higher conductivity with higher temperature—fits a semiconductor best. An alloy doesn’t inherently define this temperature-driven trend, so it doesn’t match as cleanly.