Question

Find the hot resistance of a light bulb rated 70W, 120V.

Answer 1

The hot resistance of a light bulb is 205.714 ohms.

Step-by-step explanation:

Hot resistance can be found by using Ohm's Law and definition of power, whose expression as a function of power and voltage is:

`R = (V^(2))/(\dot W)`

Where:

`\dot W` - Power, measured in Watts.

`V` - Voltage, measured in Volts.

`R` - Resistance, measured in Ohms.

Given that
`V = 120\,V` and
`\dot W = 70\,W`, we find that hot resistance is:

`R = ((120\,V)^(2))/(70\,W)`

`R = 205.714\,\Omega`

The hot resistance of a light bulb is 205.714 ohms.