JEE Advanced · Physics · 20. Magnetism & Current
Two concentric circular loops, one of radius and the other of radius , lie in the -plane with the origin as their common center, as shown in the figure. The smaller loop carries current in the anti-clockwise direction and the larger loop carries current in the clockwise direction, with denotes the magnetic field at a point in the -plane. Which of the following statement(s) is (are) correct?

- A is perpendicular to the -plane at any point in the plane
- B depends on and only through the radial distance
- C is non-zero at all points for
- D points normally outward from the -plane for all the points between the two loops
Answer & Solution
Correct Answer
(B) depends on and only through the radial distance
Step-by-step Solution
Detailed explanation
(A) Magnetic field at the plane of the ring is perpendicular to the plane. However, they bend as they move forward.
(B) By symmetry, we can say thatwill be same at all the points having the same radial distance. sowill depend only the radial distance
(C)Since,soat the centre will be non-zero indirection, But at some other point,may be zero.
From the graph, it is clear thatfor some value of. Sooption (C) is incorrect
(D) For the graph, it is clear thatindirection for, so option D is also incorrect.
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