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What is resistivity,? |
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Answer» The resistivity of a material is the resistance of a wire of that material of unit length and unit cross-sectional area. The unit for resistivity is the ohm-metre.The resistivity of a material depends on its nature and the temperature of the conductor, but not on its shape and size.A good conductor has less resistivity, whereas a bad conductor or insulator has high resistivity.The resistivity of semi-conductors lies between that of conductors and insulators. The resistivity of a metallic conductor increases with an increase in its temperature, whereas the resistivity of a semi-conductor decreases with an increase in its temperature. Resistivity is given by:where, l is the length of the conductor andA is the area of the cross section of conductor.\xa0If in the above equation, we take, l\xa0= 1 m and A = 1 m2then, R = ρ\xa0Therefore, resistivity is defined as the resistance per unit length per unit area of scross-section.\xa0SI unit of resistivity is Ohm metre.\xa0We have,\xa0\xa0SI unit of resistivity =\xa0 |
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