Gujarat BoardEnglish MediumSTD 12 SciencePhysicsSemiconductor Electronics: Materials, Devices and Simple Circuits3 Marks
Question
Classify metals, conductors and semiconductors.
✓
Answer
On the basis of conductivity : On the basis of relative value of electrical conductivity ( $\sigma$ ) or resistivity ( $\rho=$ $1 / \sigma$ ) solid materials are classified as follows : (i) Metals: Their resistivity is very low (or conductivity is very high). $\begin{array}{l} \rho \sim 10^{-2}-10^{-8} \Omega m \\ \sigma \sim 10^2-10^8 Sm^{-1} \end{array}$ (ii) Semiconductors : Their resistivity or conductivity is between metals and insulating materials. $\begin{array}{l} \rho \sim 10^{-5}-10^6 \Omega m \\ \sigma \sim 10^5-10^{-6} Sm^{-1} \end{array}$ (iii) Insulators : Their resistance is very high (or conductivity is very low). $\begin{array}{l} \rho \sim 10^{11}-10^{19} \Omega m \\ \sigma \sim 10^{-11}-10^{-19} Sm^{-1} \end{array}$ The values of $\rho$ and $\sigma$ given above are only indicative of the order value and may go outside the given range.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.