What effect does increasing the number of turns in the secondary coil have in a step-up transformer?

Increasing the number of turns in the secondary coil of a step-up transformer results in an increase in the output voltage. This phenomenon is governed by the principles of electromagnetic induction and the transformer equation, which states that the ratio of the output voltage to the input voltage is directly proportional to the ratio of the number of turns in the secondary coil to the number of turns in the primary coil.

As the number of turns in the secondary coil increases, the transformer is able to convert a greater amount of the input voltage into a higher output voltage. In a step-up transformer specifically, this design is intended to increase the voltage level while decreasing the current proportionally, in accordance with the law of conservation of energy. The transformation ratio allows for effective voltage stepping without compromising energy conservation principles.

Therefore, the correct answer illustrates the fundamental operational principle of a step-up transformer, which is to elevate voltage while maintaining the energy balance throughout the transformation process.