NEET2014PhysicsMagnetic Effects of CurrentActual
Two parallel long wires A and B carry currents i₁ and i₂ ( < i₁ ) . When i₁ and i₂ are in the same direction, the magnetic field at a point mid way between the wires is 10 T . If i₂ is reverse the field becomes 30 T . The ratio i₁ / i₂ is
Options
- A1
- B2
- C3
- D4
Correct answer
B. 2
Step-by-step solution
₀ 4 2 i₁ r - ₀ 4 2 i₂ r =10 T ₀ 4 2 i₁ r + ₀ 4 2 i₂ r =30 T On solving i₁=20 ~A and i₂=10 ~A . i₁ / i₂=2