JEE Main 2021 — Current Electricity Question with Solution
From: JEE Main 2021 (Online) 24th February Evening Shift
Question
A cylindrical wire of radius 0.5 mm and conductivity 5 107 S/m is subjected to an electric field of 10 mV/m. The expected value of current in the wire will be x3 mA. The value of x is _________.
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Show full solutionCorrect answer: 5
Correct answer
5
Step-by-step explanation
We know that current density,
J = E
J = 5 107 10 103
J = 50 104 A/m2
Current flowing;
I = J R2
I = 50 104 (0.5 103)2
I = 5 104 0.25 106
I = 125 103
x = 5
J = E
J = 5 107 10 103
J = 50 104 A/m2
Current flowing;
I = J R2
I = 50 104 (0.5 103)2
I = 5 104 0.25 106
I = 125 103
x = 5
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This is a previous-year question from JEE Main 2021, covering the Current Electricity chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.