A toroid of n turns, mean radius R and cross-sectional radius a carries current I. It is placed on a horizontal table taken as xy-plane. Its magnetic moment m
(a) Is non-zero and points in the z-direction by symmetry
(b) Points along the axis of the toroid (m = m?)
(c) Is zero, otherwise there would be a field failing as 1/r³ at large distances outside the toroid
(d) Is pointing radially outwards.

The main topic of this chapter includes - Ampere's Circuital Law, magnetic field lines, and Gauss's Law.

In JEE Main exam, it is a significant chapter. There can be 6 to 8 questions from this chapter, a weightage of nearly 6.6%.

The exact weightage varies from year to year. This chapter comes under a broader category which can be "Magnetism" or "Modern Physics". In NEET exam, the chapter's weightage is low to moderate and there can be 6-7% of questions from this chapter.

The chapter is one of the small and easy chapter of class 12 Physics. It includes - properties of magnetic materials, magnetic dipoles, and Earth's magnetic field.

When the electric charges moves, it creates attraction or repulsion. It creates magnetic forces and fields and called magnetism. The term "magnetism and matter" talks about the way magnetic forces and matter interact.