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JEE Main202324 Jan 2023Morning ShiftPhysicsCurrent ElectricityActual

A hollow cylindrical conductor has length of 3 . 14 m , while its inner and outer diameters are 4 mm and 8 mm respectively. The resistance of the conductor is n × 10 - 3 Ω . If the resistivity of the material is 2 . 4 × 10 - 8 Ω m . The value of n is _____.

Correct answer

0

Step-by-step solution

Resistance of a conductor with uniform cross-section is given by, R = ρ l A In this case the cross-sectional area is π b 2 - a 2 . Therefore, R = ρ l π b 2 - a 2 = 2 . 4 × 10 - 8 × 3 . 14 3 . 14 × 4 2 - 2 2 × 10 - 6 = 2 × 10 - 3   Ω Hence, n = 2 .

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