JEE Main 2018 — Magnetic Properties Of Matter Question with Solution
From: JEE Main 2018 (Online) 15th April Morning Slot
Question
The - curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solended with turns/cm. The current that should be passed in the solended to demagnetise the ferromagnet completely is :
This question includes a diagram. The text above accompanies the figure.
Choose an option
Show full solutionCorrect option: A
Correct answer
A
Step-by-step explanation
Given that,
In the solenoid there is 1000 turns in 1 cm.
In 100 cm or 1 m no of turns
= 1000 100 = 105 turns/m
No of turns, n = 105
Correctivity of ferromagnet, H = 100 A/m
As we know,
H = n I
I =
Current to demagnetise the ferromagnet = 1 mA.
In the solenoid there is 1000 turns in 1 cm.
In 100 cm or 1 m no of turns
= 1000 100 = 105 turns/m
No of turns, n = 105
Correctivity of ferromagnet, H = 100 A/m
As we know,
H = n I
I =
Current to demagnetise the ferromagnet = 1 mA.
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This is a previous-year question from JEE Main 2018, 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.