Question

For an ideal step-down transformer, the quantity which is constant for both the coils is

• A. current in the coils
• B. voltage across the coils
• C. resistance of coils
• D. power in the coils

Answer 1

Answer: (D)

power in the coils

Answer 2

For an ideal step-down transformer, power is constant for both the coils.
i.e. Input power = Output power
$\therefore V_{p}I_{p}=V_{s}I_{s}$ or $\frac{V_{p}}{V_{s}}=\frac{I_{s}}{I_{p}}$