MHT CET202618 April 2026Morning ShiftPhysicsMagnetic Effects of CurrentActual
In the following figure, the magnitude of the magnetic field at point 'O' will be
Options
- A₀ 4 I r ( 2 +2 )
- B₀ 4 I r ( 2 -2 )
- C₀ 4 I r (2+ 2 )
- D₀ 4 I r (2- 2 )
Correct answer
C. ₀ 4 I r (2+ 2 )
Step-by-step solution
The magnetic field at point O is the vector sum of the magnetic fields produced by the three segments of the current-carrying wire: the semi-infinite straight wire AB , the quarter-circular arc BC , and the semi-infinite straight wire CD . For the semi-infinite straight wire AB , the perpendicular distance from O is r . One end of the wire is at B (subtending angle 0^ ) and the other extends to infinity (subtending angle 90^ ). The magnitude of the magnetic field at O is: B₁ = ₀ I 4 r ( 90^ + 0^ ) = ₀ I 4 r By the