If the primary voltage (Ep) is 120 volts, the primary current (Ip) is 5 amps, and the secondary current (Is) is 2 amps, what is the secondary voltage (Es)?

To determine the secondary voltage (Es), we can use the principle of power conservation in electrical systems, especially in transformer applications. The power in the primary side (input power) must equal the power in the secondary side (output power), assuming an ideal transformer without losses.

The power can be calculated using the formula:

Power (P) = Voltage (V) × Current (I)

For the primary side:

Pp = Ep × Ip

Pp = 120 volts × 5 amps = 600 watts

For the secondary side:

Ps = Es × Is

Since Pp = Ps, we can set the two equations equal to each other:

600 watts = Es × 2 amps

Now, we can solve for the secondary voltage (Es):

Es = 600 watts / 2 amps = 300 volts

Therefore, the secondary voltage (Es) is 300 volts, which corresponds to the value provided in the answer. This aligns with the concept that when dealing with transformers, the relationship of the currents and voltages are related to ensure the power remains constant across the primary and secondary sides.