JEE Main 2026 — Magnetic Properties of Matter Question with Solution
JEE Main 2026 (23 January Shift 1)
Question
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Consider a ferromagnetic material :
Assertion (A) : The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a way that they spontaneously align themselves forming domains.
Reason (R): At high enough temperature, the domain structure of ferromagnetic material disintegrates. Thus, magnetization will disappear at high enough temperature known as Curie temperature.
In the light of the above statements, choose the correct answer from the options given below :
Consider a ferromagnetic material :
Assertion (A) : The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a way that they spontaneously align themselves forming domains.
Reason (R): At high enough temperature, the domain structure of ferromagnetic material disintegrates. Thus, magnetization will disappear at high enough temperature known as Curie temperature.
In the light of the above statements, choose the correct answer from the options given below :
Choose an option
Show full solutionCorrect option: B
Correct answer
BBoth (A) and (R) are true but (R) is not the correct explanation of (A)
Step-by-step explanation
Assertion (A) states that individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact to form domains. This is a correct description of the domain theory of ferromagnetism, where exchange interactions lead to spontaneous alignment of moments within small regions called domains.
Reason (R) states that at high temperatures (above the Curie temperature ), the domain structure disintegrates due to thermal agitation, and the material becomes paramagnetic. This is also a correct statement regarding the temperature dependence of ferromagnetic materials.
However, Reason (R) describes the effect of temperature on the domain structure, whereas Assertion (A) describes the fundamental nature and formation of domains in the ferromagnetic state. The disintegration of domains at high temperature is not the reason why they form spontaneously at lower temperatures. Therefore, both statements are true, but (R) is not the correct explanation of (A).
Reason (R) states that at high temperatures (above the Curie temperature ), the domain structure disintegrates due to thermal agitation, and the material becomes paramagnetic. This is also a correct statement regarding the temperature dependence of ferromagnetic materials.
However, Reason (R) describes the effect of temperature on the domain structure, whereas Assertion (A) describes the fundamental nature and formation of domains in the ferromagnetic state. The disintegration of domains at high temperature is not the reason why they form spontaneously at lower temperatures. Therefore, both statements are true, but (R) is not the correct explanation of (A).
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This is a previous-year question from JEE Main 2026, covering the Magnetic Properties of Matter chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.