There is magnetic material of coercivity 2 x 10^3 A/m. What current should flow through the solenoid of length 15 cm having 150 turns to demagnetize the substance completely?
Correct answer: C. 2 A
- A. 4 A
- B. 2.5 A
- C. 2 A
- D. 3.5 A
Explanation
H = 2 × 10³, for solenoid H = n In = 150 / (15 × 10⁻²) = 1000⇒ I = H / n = (2 × 10³) / 10³ = 2 A.
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