M=Vmagneticmoment(m)
⇒χH=Vm
⇒m=(μr−1)NiV
∴mΔm=(500−1)NiV[(750−1)−(500−1)]NiV=250
JEE Main 2021 — Physics Electromagnetism
A long solenoid with 1000turnsm−1 has a core material with relative permeability 500 and volume 103cm3. If the core material is replaced by another material having relative permeability of 750 with same volume maintaining same current of 0.75A in the solenoid, the fractional change in the magnetic moment of the core would be approximately (499x). Find the value of x.
Held on 31 Aug 2021 · Verified 6 Jul 2026.
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