A transformer primary winding consumes 10 watts. Neglecting losses, if the secondary voltage is 5 volts, what is the secondary current?

In an ideal transformer with 100% efficiency, the power consumed by the primary winding is exactly equal to the power delivered by the secondary winding. Therefore, if the primary consumes 10 watts, the secondary also outputs 10 watts. To find the secondary current, you use the standard power formula: Power (P) = Voltage (E) x Current (I). By rearranging the formula to solve for current (I = P / E), you divide the 10 watts of power by the 5 volts on the secondary. This results in a secondary current of 2 amperes.