Final answer:
In a step-down transformer, more current will flow in the secondary circuit of a 40 VA transformer than in the secondary circuit of a 100 VA transformer due to the higher number of turns in the secondary winding.
Step-by-step explanation:
Transformers are devices that can step up or step down the voltage of an electrical circuit. A step-up transformer increases the voltage and decreases the current, while a step-down transformer decreases the voltage and increases the current. The ratio of the secondary to primary voltages in a transformer is equal to the ratio of the number of turns in their windings.
Therefore, in the case of a 40 VA transformer compared to a 100 VA transformer, the 40 VA transformer would have a higher current in its secondary circuit. This is because the 40 VA transformer has a larger number of turns in its secondary winding compared to the primary winding, resulting in a higher secondary voltage and therefore a higher current.