PYQ Vault

Playbook

Magnetism and Matter

Bar magnets, the earth's field and magnetic materials. A small chapter, mostly recall of the material classes.

Questions in the bank
46
q/paper in 2025–26
0.27
Numeric answer
22%
Notes pages
3

Tier: Long tail

When you’ll see it

A bar magnet or coil turned in a uniform field, the earth's field and the angle of dip, or a statement about a magnetic material, its susceptibility or its hysteresis loop.

How this chapter is tested

Magnetism and Matter is a small chapter in the long tail. About half of it is magnetic materials, and those are mostly statements to judge, each settled by one exact fact about susceptibility, temperature or the hysteresis loop.

The largest group of calculations turns a magnet or a coil in a uniform field and needs only the torque MB sin θ and the energy −MB cos θ, read with the right angle. The earth's field and the angle of dip have not appeared on the recent papers, so they come last in the order of study.

Marks are lost on the sign of the energy, on reading a coil's plane as its moment, and on calling a strongly attracted material paramagnetic. The dipole page is the magnetic twin of the electric dipole in Electrostatics, and a coil's moment NIA comes from Moving Charges and Magnetism.

The sub-skills

The distinct skills inside the chapter, in the order to learn them.

  • Bar magnets and dipoles

    A moment M whose field falls as 1/r³, the axial value twice the equatorial; in a uniform field a torque MB sin θ and an energy −MB cos θ.

  • The earth's field

    Horizontal part B cos δ and vertical part B sin δ; the horizontal part cancels a magnet's field at a neutral point and sets the period of a magnet swinging horizontally.

  • Magnetic materials and hysteresis

    M = χH and μᵣ = 1 + χ; the sign and size of χ sort diamagnets, paramagnets and ferromagnets; soft iron for an electromagnet has high permeability and low retentivity and coercivity.

Traps to expect

Distractor shapes this chapter reuses. The Traps page covers the ones that cut across chapters.

  • A positive energy

    U = −MB cos θ is negative at angles below 90°. An option with the right size and a positive sign is a deliberate trap.

  • A coil's plane read as its moment

    A coil's moment is along the normal to its plane. A plane perpendicular to B puts the moment along B, the stable position with no torque.

  • Strong attraction called paramagnetic

    Paramagnets are attracted only weakly; strong attraction marks a ferromagnet. A paramagnet moves towards a stronger field, a diamagnet away from it.

  • Retentivity and coercivity swapped

    Retentivity is a value of B, read where the loop cuts the B-axis. Coercivity is a value of H, read where it cuts the H-axis.

Learn it before you drill it

This chapter has full teaching notes — foundations, worked examples, self-checks and a mastery check for each page. Read the notes once, then drill page by page below.

Magnetism and Matter notes

Drill every Magnetism and Matter question

46 questions from the bank, across 3 subtopics.

Drill the 46 questions

Drill one subtopic at a time

The 3 subtopics, in teaching order.

Related playbooks

Often paired with this one — the technique or the trap overlaps. Drill these next.