Solenoid — Number of TurnsEasyQuestion 20235
Question
A solenoid has 500 turns, length 25 cm, and carries 2 A. Field inside (μ₀ = 4π×10⁻⁷) is:
- A4π×10⁻³ TCorrect
- B2π×10⁻³ T
- C8π×10⁻³ T
- Dπ×10⁻³ T
Correct answer
4π×10⁻³ T
Explanation
n = 500/0.25 = 2000 turns/m. B = μ₀nI = 4π×10⁻⁷ × 2000 × 2 = 16π×10⁻⁴ T = 4π×10⁻³ T.