How is the relationship between voltage and the number of turns in a transformer characterized?

The relationship between voltage and the number of turns in a transformer is characterized as directly proportional. This means that as the number of turns in the primary winding increases, the voltage induced in the secondary winding also increases, assuming other factors, such as the magnetic flux and frequency, remain constant.

In a transformer, the voltage ratio between the primary and secondary coils is determined by the ratio of their turns. For instance, if the primary coil has more turns than the secondary coil, the transformer is a step-down transformer, reducing the voltage. Conversely, if the secondary coil has more turns, it acts as a step-up transformer, increasing the voltage. This fundamental principle underlies the operation of transformers and is rooted in Faraday's laws of electromagnetic induction, which state that the induced voltage in a coil is proportional to the rate of change of magnetic flux, which directly relates to the number of turns in the coil.

The other choices either do not accurately represent the nature of this relationship or misinterpret the factors that affect voltage in a transformer setup.