JEE Main 2022 · 25 Jul · Shift 1 · Physics Q58

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PhysicsInteger+4 / -1Question 58 of 90

Eight copper wire of length $l$ and diameter d are joined in parallel to form a single composite conductor of resistance R. If a single copper wire of length $2l$ have the same resistance (R) then its diameter will be ______ d.

Your answer

Answer and worked solution

Official answer: 4

Equal resistance. Eight in parallel: $\frac{\rho l}{8A}$ . Single wire: $\frac{\rho\,2l}{A'}$ , so $A'=16A$ and the diameter is $4d$ .

Answer: 4

Topics:Ohm's law and resistivity Series and parallel resistors

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JEE Main 2022 · 25 Jul · Shift 1, Physics question 58