Question

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 ______.

Options

• 285 A/m

• 2600 A/m

• 520 A/m

• 1200 A/m

Answer 1

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 2600 A/m.

Explanation:

Coercivity, H = `"B"/mu_0` and B = μ₀ni `("n" = "N"/ℓ)`

or, H = ` "N"/ℓ"i"`

= `100/0.2xx5.2`

= 2600 A/m