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Question: Answered & Verified by Expert
A current of 5 A is passing through a non-linear magnesium wire of cross-section 0.04 m2. At every point the direction of current density is at an angle of 60° with the unit vector of area of cross-section.
The magnitude of electric field at every point of the conductor is: (resistivity of magnesium ρ=44×10-8 Ωm)
PhysicsCurrent ElectricityJEE MainJEE Main 2021 (20 Jul Shift 1)
Options:
  • A 11×10-2 V m-1
  • B 11×10-7 V m-1
  • C 11×10-5 V m-1
  • D 11×10-3 V m-1
Solution:
1405 Upvotes Verified Answer
The correct answer is: 11×10-5 V m-1
I=J·A=JAcos(θ)
5=J4100×cos(60)
J=5×50=250 A m-2
Now, E=ρ×J
=44×10-8×250=11×10-5 V m-1

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