NTA Abhyas JEE Main2020PhysicsMagnetic Effects of CurrentPractice
A wire in the form of a square of side a carries a current i . Then, the magnetic induction at the centre of the square wire is (magnetic permeability of free space = μ 0 ).
Options
- Aμ 0 i 2 π a
- Bμ 0 i 2 π a
- C2 2 μ 0 i π a
- Dμ 0 i 2 π a
Correct answer
C. 2 2 μ 0 i π a
Step-by-step solution
Magnetic field due to one side of the square at centre O. B 1 = μ 0 4 π . 2 i sin 45 o a 2 ⇒ B 1 = μ 0 4 π . 2 2 i a Hence, magnetic field at centre due to all sides B n e t = 4 B 1 = μ 0 2 2 i π a