PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A student begins with Circuit 1, which contains a resistor R in series with a capacitor C. The student then constructs Circuit 2 by adding a second identical resistor R in parallel with the original resistor while leaving the capacitor unchanged. Which statement best describes how the time required for the capacitor to reach 63 percent of its final charge changes when going from Circuit 1 to Circuit 2?
(a) The charging time increases because the equivalent resistance increases.
(b) The charging time remains the same because the changes in resistance and capacitance offset each other.
(c) The charging time decreases because the equivalent resistance decreases.
(d) The charging time decreases because the equivalent capacitance decreases.