Question
Explain the classification of material in terms of resistivity.
✓
Answer
→All materials fall under any one of these categories :
(1) conductor
(2) semi conductors and
(3) insulator.
→Among conductors, semi conductors and insulators, conductors have the lowest resistivity and insulators have the highest resistivity.
→The resistivity of metals (conductors) is in the range of $10^{-8} \Omega m$ to $10^{-6} \Omega m$.
→The resistivity of an insulator is $10^{18}$ times higher than the metals.
→The resistivity of a semi conductor lies between the conductor and the insulator.
→By increasing the temperature within a certain limit, the resistivity of metals increases with temperature while the resistivity of semi conductors decreases with temperature.
→The resistivity of semi conductors is also affected by presence of small amount of impurities.
→This feature is useful to make electronic devices from the semi conductors.
(1) conductor
(2) semi conductors and
(3) insulator.
→Among conductors, semi conductors and insulators, conductors have the lowest resistivity and insulators have the highest resistivity.
→The resistivity of metals (conductors) is in the range of $10^{-8} \Omega m$ to $10^{-6} \Omega m$.
→The resistivity of an insulator is $10^{18}$ times higher than the metals.
→The resistivity of a semi conductor lies between the conductor and the insulator.
→By increasing the temperature within a certain limit, the resistivity of metals increases with temperature while the resistivity of semi conductors decreases with temperature.
→The resistivity of semi conductors is also affected by presence of small amount of impurities.
→This feature is useful to make electronic devices from the semi conductors.
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