In an ideal transformer, if the primary turns double while the secondary turns stay the same and the primary voltage is fixed, what happens to the secondary voltage?

In an ideal transformer, if the primary turns double while the secondary turns stay the same and the primary voltage is fixed, what happens to the secondary voltage?

• A. It remains the same
• B. It doubles
• C. It halves
• D. It becomes zero

Answer: (C)

In an ideal transformer, voltages scale with the turns ratio: Vp/Vs = Np/Ns. If the primary voltage is fixed and the secondary turns stay the same, doubling the primary turns makes the ratio Np/Ns twice as large. To keep the relationship consistent, the induced secondary voltage must drop by the same factor, so Vs becomes half of what it was. In formula form, Vs = Vp × Ns / Np, so increasing Np while keeping Vp fixed lowers Vs proportionally. Therefore, the secondary voltage halves.

In an ideal transformer, voltages scale with the turns ratio: Vp/Vs = Np/Ns. If the primary voltage is fixed and the secondary turns stay the same, doubling the primary turns makes the ratio Np/Ns twice as large. To keep the relationship consistent, the induced secondary voltage must drop by the same factor, so Vs becomes half of what it was. In formula form, Vs = Vp × Ns / Np, so increasing Np while keeping Vp fixed lowers Vs proportionally. Therefore, the secondary voltage halves.