Question

Does a step up transformer contradict the principle of conservation of energy? Justify your answer.

Hint:

Think of a transformer like a see-saw: if one side (Voltage) goes up, the other side (Current) must go down to keep the system in balance. You never get "free" power!

Answer 1

Does a Step-Up Transformer Violate the Law of Conservation of Energy?
No, a step-up transformer does not contradict the principle of conservation of energy.

Understanding the Working of a Step-Up Transformer
In a step-up transformer, the secondary voltage is greater than the primary voltage.
This happens because the number of turns in the secondary coil is greater than in the primary coil.
The voltage and turns ratio relation is:
V_s / V_p = N_s / N_p
Since N_s > N_p, we get V_s > V_p.

Power Relation in an Ideal Transformer
In an ideal transformer (no losses), input power equals output power.
P_input = P_output
V_p I_p = V_s I_s
If the voltage increases in the secondary (V_s > V_p), then the current must decrease accordingly (I_s < I_p).
Thus:
Increase in voltage is accompanied by decrease in current.

Energy Conservation Explanation
A transformer does not create extra energy.
It only changes the ratio of voltage and current while keeping total power constant (neglecting losses).
Therefore:
Higher voltage × lower current = Same power
In practical transformers, some energy is lost due to:
- Copper losses
- Core losses
- Eddy currents
So the output power is slightly less than input power.

Conclusion:
A step-up transformer does not violate the law of conservation of energy. It increases voltage but decreases current so that total power remains conserved. Hence, energy is neither created nor destroyed.