Conductivity of a material is highest in:
- Semiconductor
- Vacuum
- Insulator
- Metal (conductor)
Show answer and solution
Correct answer: D. Metal (conductor)
Metals have very high conductivity (~10⁷ S/m) due to free electrons.
Semiconductors are intermediate (10⁻⁴ to 10⁴ S/m), insulators very low (<10⁻⁸ S/m).