Transformer power conservation (ideal case): With 100% efficiency (no losses), the power transferred to the secondary equals the power drawn from the primary, independent of step-up or step-down operation.

Introduction / Context:
Transformers transfer power between circuits via magnetic coupling. In the ideal case of 100% efficiency, the power into the primary equals the power delivered by the secondary. This principle underlies transformer ratings, turns-ratio design, and safety considerations in power systems and electronics.

Given Data / Assumptions:

• Ideal (lossless) transformer: no copper loss, core loss, or leakage.
• Arbitrary turns ratio may step voltage up or down.
• Power factor may be anything; equality is for real power values.

Concept / Approach:
For an ideal transformer, Vp/Vs = Np/Ns and Ip/Is = Ns/Np. Apparent power balance gives Vp * Ip = Vs * Is. When no losses exist, input real power equals output real power even if voltage and current magnitudes change. The transformer trades current for voltage according to the turns ratio while conserving power.

Step-by-Step Solution:

Verification / Alternative check:
Measure primary and secondary wattage with a true wattmeter under a resistive load; losses in practical units introduce small discrepancies but the ideal model remains an excellent approximation.

Why Other Options Are Wrong:
Limiting the statement to step-up or step-down is unnecessary. Unity power factor is not required for power equality; it affects currents and voltages but not ideal conservation.

Common Pitfalls:
Confusing apparent power S with real power P when power factor is not unity, and misinterpreting the roles of core and copper losses in non-ideal transformers.

Final Answer:
Correct