SI unit of resistivity is _
Correct answer: C. Ω-m
- A. Ω-m2
- B. (Ω-m)-1
- C. Ω-m
- D. (Ω-m)-2
Explanation
Resistivity (ρ) is a fundamental property of materials that quantifies how strongly a material opposes the flow of electric current. It is given by the equation ρ = RA/L, where R is resistance, A is cross-sectional area, and L is length. Substituting the respective units, we get ρ = Ω × m²/m = Ωm, making Ωm the correct SI unit for resistivity.Option A (Ω-m2) is incorrect because it is not a recognized unit for resistivity. Option B ((Ω-m)-1) is incorrect as it represents the unit of conductivity, the reciprocal of resistivity. Option D ((Ω-m)-2) is incorrect since it does not correspond to any meaningful electrical property.
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About Resistance and Resistivity
Resistance measures opposition to current in a conductor and follows R = V/I for an ohmic conductor, while resistivity is an intrinsic property of the material. Questions use R = ρL/A, examine effects of length, cross-sectional area and temperature, and distinguish resistance, resistivity, conductance and conductivity.
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