Concept:

A transformer modifies voltage and current levels through mutual induction but cannot change the timing frequency of the alternating source.

Solution:

While a transformer can step up/down both voltage and current, the rate of change of magnetic flux is governed strictly by the source. Consequently, the frequency of the alternating electric signal remains completely invariant between the primary and secondary circuits.

Note: In an ideal transformer, the electrical power is also conserved (\( P_{\text{in}} = P_{\text{out}} \)), but in any real, practical transformer, power decreases due to heat and flux losses. Frequency is the only quantity that is strictly conserved in all cases.

Why other options are incorrect:

• Voltage and Current are modified by the turns ratio \( \frac{N_s}{N_p} \).



• Power drops in all non-ideal transformers due to hysteresis, copper losses, and eddy currents.