Subelement B: Electrical Math— Topic 13: Power Relationships
Question 3-13B2
Element 3 (GROL)If a resistance to which a constant voltage is applied is halved, what power dissipation will result?
Explanation
When a constant voltage is applied to a resistance, the power dissipated is given by the formula P = V²/R, where P is power, V is voltage, and R is resistance.
In this scenario, the voltage (V) remains constant. If the resistance (R) is halved, the new resistance becomes R/2. Substituting this into the formula:
New Power = V² / (R/2)
New Power = 2 * (V²/R)
New Power = 2 * Old Power
Therefore, if the resistance is halved while the voltage remains constant, the power dissipation will double. This is because power is inversely proportional to resistance when voltage is constant.
A) Double is correct.
B) Halved would occur if the resistance doubled.
C) Quadruple would occur if the resistance was quartered, or if the voltage doubled (keeping R constant).
D) Remain the same is incorrect, as changing resistance with constant voltage will alter power.
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