Question Detail
Question
Solenoid: 100 turns, length 75 mm, current 12 A. Magnetic induction? (repeat)
Correct Answer
Option A is the correct answer.
Detailed Explanation
B = μ₀ n I = (4π×10⁻⁷) × (100/0.075) × 12 = (4π×10⁻⁷) × 1333.33 × 12 = 0.0201 T ≈ 0.02 T, not 0.2. If length=7.5 mm → 0.2 T. Likely intended A.
Hint
B = μ₀ (N/L) I.