Question Detail

PHY 102 Last Minute Prep Objective Question

Question

A 2μF capacitor charged to 50V is discharged through a 1MΩ resistor. Find time to drop to 25V.
Options
A 0.5s
B 0.72s
C 0.27s
D 1.39s
Correct Answer
Correct Answer

Option D is the correct answer.

Detailed Explanation

V(t) = V₀e^(-t/RC). 25 = 50e^(-t/2). t = -2ln(0.5) = 1.386s. RC = (1×10^6)(2×10^-6) = 2s.

Hint

Use the discharge equation V(t) = V₀e^(-t/RC).

Question Info