Question

You have a nightlight plugged into an outlet in the hallway, which uses 3.5 watts when plugged in. If the house circuit provides 120.0 volts, what is the current through this bulb?

Answer 1

This problem can be solved by manipulating the formula for power, which is: P = VI. Where:

P = Power in watts
V= Voltage in volts
I = Current in amperes

Since we are already given the power and voltage, simple substitution can be done.

P = VI
3.5 watts = 120 volts * I
I = 3.5 / 120
I = 0.0292 Amperes or 29.2 milliAmperes

Therefore, the current through the bulb is 29.2mA