Question

What is the voltage output of a transformer used for rechargeable flashlight batteries, if its primary has 500 turns, its secondary 4 turns, and the input voltage is 120 V?

a) 1.5 V
b) 30 V
c) 1500 V
d) 480 V

Answer 1

The voltage output of the transformer with 500 turns on the primary, 4 turns on the secondary, and an input voltage of 120 V is approximately 0.96 V. When rounded to the nearest option provided, the answer is 1.5 V.

Step-by-step explanation:

To determine the voltage output of the transformer used for rechargeable flashlight batteries, we need to apply the transformer equation which relates the primary and secondary voltages and the number of turns on the primary (Np) and secondary (Ns) coils:

Vp/Vs = Np/Ns

Where Vp is the primary voltage, Vs is the secondary voltage, Np is the number of primary windings, and Ns is the number of secondary windings.

Given that the transformer's primary has 500 turns, its secondary 4 turns, and the input voltage (Vp) is 120 V, we can rearrange the formula to solve for the secondary voltage (Vs):

Vs = Vp * (Ns / Np)
Vs = 120 V * (4 turns / 500 turns)
Vs = 120 V * 0.008
Vs = 0.96 V

However, since the options provided do not include 0.96 V, and we must select one, the closest one, which is essentially a result of rounding off, would be 1.5 V (option a).