AP EAMCET201726 Apr 2017Morning ShiftPhysicsMagnetic Effects of CurrentActual
Two concentric coils of 20 turns each are placed in same plane. Their radii are 30 ~cm and 60 ~cm and carry 0.4 ~A and 0.6 ~A currents respectively in opposite directions. The magnetic induction at the centre in tesla is ....... .
Options
- A8 3 ₀
- B2 3 ₀
- C5 3 ₀
- D10 3 ₀
Correct answer
D. 10 3 ₀
Step-by-step solution
As B_ centre = ₀ n I 2 r So, Magnetic field at O , aligned & B_O= ₀ 2 [ n₁ I₁ r₁ - n₂ I₂ r₂ ] & n₁=n₂=20 & B_O= ₀ 4 2 20 [ 0.4 30 10⁻² - 0.6 60 10⁻² ] & = ₀ 2 20 [ 0.8-0.6 60 10⁻² ]= 10 3 ₀ aligned