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
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
Based on the problem statement’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 statement’s knowns:
$$$P=I^2R\to 500W=I^2(40\Omega)$$$
$$$I=\sqrt{\frac{500W}{40\Omega}}=3.5\:A$$$
3.5 A
Time Analysis
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