## Current

Consider an electric space heater is built with a 40 ohm resistor. How much current (amps) is needed to produce 500 W of heat?

##
__
__**Expand Hint**

**Expand Hint**

Power absorbed by a resistive element:

$$$P=VI=\frac{V^{2}}{R}=I^2R$$$

where
$$V$$
is voltage,
$$I$$
is current, and
$$R$$
is resistance.

##
__
__**Hint 2**

**Hint 2**

Based on the problem statementâ€™s givens, solve for current using the equation:

$$$P=I^2R$$$

Power absorbed by a resistive element:

$$$P=VI=\frac{V^{2}}{R}=I^2R$$$

where
$$V$$
is voltage,
$$I$$
is current, and
$$R$$
is resistance.

Solving for Current using the problem statementâ€™s knowns:

$$$P=I^2R\to 500W=I^2(40\Omega)$$$

$$$I=\sqrt{\frac{500W}{40\Omega}}=3.5\:A$$$

3.5 A

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Similar Problems from FE Section:

**Electrostatics**010. Electric Vehicle Basics

066. Powering a Motor

116. Power

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134. Hot Pot

181. Resistors in Parallel

185. Resistors in Series

291. Heating Element

439. Toaster Oven Resistor

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512. Voltage

521. Custom PC