Physics · Magnetism And Matter · NEET
Attracted, but only WEAKLY. Its atoms already carry permanent magnetic dipoles. In an external field these dipoles turn to point along the field, so the material develops a net moment in the same direction as the field and is pulled toward the stronger-field region. The pull is small because thermal motion keeps knocking the dipoles out of alignment. Contrast: diamagnetic = weakly repelled, ferromagnetic = strongly attracted.
Susceptibility χ = M/H. In a paramagnet the magnetisation M points ALONG H (dipoles align with the field), so χ is positive. It is small because random thermal motion opposes the alignment, so only a tiny fraction of dipoles line up at ordinary field strengths. Typical χ is about +10^-5 to +10^-3, and relative permeability μ_r = 1 + χ is just slightly above 1.
Heating adds thermal agitation that fights the alignment, so paramagnetism gets WEAKER as temperature rises. Curie's law states χ = C/T, where C is the Curie constant and T is absolute temperature. So χ is inversely proportional to T: a graph of χ versus 1/T is a straight line through the origin. This is a very common NEET graph question.
Aluminium, sodium, calcium, chromium, platinum, manganese, oxygen gas, and salts like copper chloride. Remember them as materials whose atoms have unpaired electrons (net atomic dipole). If asked in NEET, pick a metal or gas with an odd/unpaired electron structure — that is the tell for paramagnetism.
It moves from the weaker-field region toward the STRONGER-field region and its long axis lines up PARALLEL to the field. This is because it is weakly attracted. A diamagnetic rod does the opposite (moves to weaker field, aligns perpendicular). NEET often asks you to predict this motion, so pair 'para = to strong field, parallel' with 'dia = to weak field, perpendicular'.
The variation of susceptibility (χ) with absolute temperature (T) for a paramagnetic material is best represented by a graph of χ against 1/T. Which shape is correct?
Match the material with its susceptibility (χ): A. Diamagnetic B. Ferromagnetic C. Paramagnetic D. Non-magnetic with I. χ = 0 II. 0 > χ ≥ −1 III. χ >> 1 IV. 0 < χ < ε (small positive).
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Much weaker. Paramagnets have χ of about +10^-5 to +10^-3, while ferromagnets have χ >> 1 (thousands). Both are attracted along the field, but ferromagnetic attraction is very strong and can remain after the field is removed; paramagnetic attraction is tiny and vanishes when the field is off.
No. Once the external field is removed, thermal motion randomises the dipoles again and the net magnetisation drops to zero. Only ferromagnets retain magnetisation (this retained magnetism is why permanent magnets exist).
Atoms with unpaired electrons have a permanent net magnetic dipole moment. Normally these point in random directions and cancel out. An external field partly lines them up along itself, giving a small net moment in the field's direction — that is paramagnetism.
Yes. Liquid oxygen sticks between the poles of a magnet because O2 molecules have unpaired electrons giving each a permanent dipole. This is a classic example used to show weak attraction (paramagnetism).
Slightly greater than 1, because μ_r = 1 + χ and χ is a small positive number. So a paramagnet lets magnetic field lines pass slightly more easily than vacuum, but the effect is tiny compared with a ferromagnet.
