Question

Two coplanar concentric circular coils of radii r and 2r, have the same number of turns n. The smaller coil carries a clockwise current i, while the larger coil carries an anticlockwise current 2i. The magnetic field induction at the centre is

Answer 1

Explanation:

Given Two coplanar concentric circular coils of radii r and 2r, have the same number of turns n. The smaller coil carries a clockwise current i, while the larger coil carries an anticlockwise current 2i. The magnetic field induction at the centre is

• Now there are two concentric circular coils
• Now the inner radius is r and the outer radius is 2r. Both have the same number of turns. The inner circle carries a current I in the clockwise direction while the outer circle carries a current 2i in the anticlockwise direction.
• We need to find the magnetic field induction at the centre due to these two loops.
• Now for the inner loop, the magnetic induction
•                                  B (inner) = μo ni / 2r
• So for the outer loop, the magnetic induction will be
•                                 B (outer) = μo n 2I / 2 x 2r
•                                                 = μo n I / 2r
• Now both B inner and B outer has same magnitude but opposite direction. The current is opposite in both cases.
• Therefore net magnetic field that is difference between the two B inner and B outer will be zero.
• So magnetic induction at the centre is 0

Reference link will be

https://brainly.in/question/16519894