Physics question

Question

From one coil of a transformer to another, which of the following quantities ALWAYS stays constant (does not change)?

A. Voltage

B. Current

C. Energy

D. Resistance

Answer 1

An ideal transformer "transforms" an AC input to another voltage (could be higher or lower). The transformation is determined by the ratio of the number of turns of wire. If the secondary (output side) has more turns than the primary, it will have a higher voltage----the RATIO of the voltages will be the same as the ratio of the number of turns.

In the ideal transformer, there is no DC resistance in the windings, and the input power and output power are the same.