Solve.
-The power that a resistor must dissipate is jointly proportional to the square of the current flowing through the resistor and the resistance of the resistor. If a resistor needs to dissipate 20 watts of power when 2 amperes of
Current is flowing through the resistor whose resistance is 5 ohms, find the power that a resistor needs to
Dissipate when 4 amperes of current are flowing through a resistor whose resistance is 7 ohms.
A) 112 watts
B) 28 watts
C) 56 watts
D) 196 watts

Question

Quizplus · Accepted Answer

The power dissipated by a resistor is given by $P = I^2R$, where $P$ is the power in watts, $I$ is the current in amperes, and $R$ is the resistance in ohms. For the first scenario, $P = 20$ watts, $I = 2$ amperes, and $R = 5$ ohms, which is consistent with the formula. For the second scenario, with $I = 4$ amperes and $R = 7$ ohms, the power dissipated is $P = 4^2 \times 7 = 16 \times 7 = 112$ watts.

Solve. -The Power That a Resistor Must Dissipate Is Jointly Proportional