NEET2026PhysicsMagnetic Effects of CurrentActual
A current I₀ flows through a metallic circular loop of radius r as shown in the figure. Resistance of the segment ABC is half that of ADC. Magnitude of magnetic field at the center O of the loop is :
Options
- A₀ I₀ 2 r
- B₀ I₀ 12r
- C₀ I₀ 4r
- D₀ I₀ 2r
Correct answer
B. ₀ I₀ 12r
Step-by-step solution
From the given figure, the dashed line passing through A, O, and C is straight, indicating that the segments ABC and ADC are semicircles. Let the resistance of segment ADC be R_ ADC = 2R . Given that the resistance of segment ABC is half that of ADC, we have R_ ABC = R . The total current I₀ splits at point A into two parallel branches. Let I₁ be the current through ABC and I₂ be the current through ADC. Since the branches are in parallel, the potential difference across them is equal: I₁ R_ ABC = I₂ R_ ADC I₁ (R)