question_answer

A bar magnet is demagnetized by inserting it inside a solenoid of length 0.2 m, 100 turns, and carrying a current of 5.2 A. The coercivity of the bar magnet is:                                                     [JEE Main 09-Jan-2019 Morning]

A) 2600 A/m

B) 1200 A/m

C)             520 A/m

D) 285 A/m

Correct Answer: A

Solution :

[a]

Option [a] is correct.