Transformer Turns Ratio

Steps:

• Calculate voltage ratio: primary voltage / secondary voltage = 230 V / 5 V = 46.
• In a transformer, turns ratio equals voltage ratio: primary turns / secondary turns = 46.
• Set up equation: 2500 / N = 46, where N is secondary turns.
• Solve for N: N = 2500 / 46 ≈ 54.

Why B is correct:

• Transformer law states Vs / Vp = Ns / Np, so Ns = Np × (Vs / Vp) = 2500 × (5 / 230) ≈ 54 turns.

Why the others are wrong:

• A. 11: Implies turns ratio of 2500/11 ≈ 227, far exceeding voltage ratio of 46.
• C. 500: Implies turns ratio of 5, matching 1/5 voltage step-down, not 1/46.
• D. 1150: Implies turns ratio of ≈2.17, for minor step-down like 230/106 V, not to 5 V.

Final answer: B