Final answer:
The voltage across a 75.0-ohm resistor that uses 0.285W of power is found using the formula P = V^2 / R. By rearranging and solving for V, the voltage is determined to be approximately 4.62 volts, which does not match any of the provided answer choices.
Step-by-step explanation:
To find the voltage across a 75.0-ohm resistor that uses 0.285W of power, we can use the formula for electrical power, which is P = V2 / R, where P is power, V is voltage, and R is resistance. By rearranging the formula to solve for V, we get V = √(P * R).
Plugging in the known values:
We get:
V = √(0.285W * 75.0 ohms) = √(21.375) ≈ 4.62 volts
However, since the given answer choices seem to suggest we are looking for an answer below 3 volts, it seems there might be an error in either the question or the answer choices provided. Based on the correct calculations, none of the options (A. 1.9V B. 2.0V C. 2.1V D. 2.2V) match the correct value of approximately 4.62 volts.