When the voltage applied to the primary side of a transformer is reduced, what happens to the output voltage?

When the voltage applied to the primary side of a transformer is reduced, the output voltage also decreases. This is due to the principle of electromagnetic induction that governs transformer operation. A transformer operates on the ratio of the number of turns of wire in the primary coil to the number of turns in the secondary coil. This ratio determines the relationship between the input (primary) voltage and the output (secondary) voltage.

If the primary voltage is lower, the magnetic field generated by the primary coil is also weaker. Consequently, the induced voltage in the secondary coil, which is dependent on the strength of that magnetic field, is reduced. Therefore, as the primary voltage decreases, the output voltage must decrease proportionally according to the turns ratio of the transformer. This direct relationship assures that any change in the primary voltage will have a corresponding effect on the output voltage.

In summary, when the primary voltage of a transformer is reduced, the output voltage consequently decreases, making this the correct answer.