A 20Ω resistor and 1000 microfarad capacitor are connected in ser
| A 20Ω resistor and 1000 microfarad capacitor are connected in series to a DC supply of 5V through a switch. What is the current through the circuit at the instant of closing the switch?
A. 1A
B. 0A
C. 0.5A
D. 0.25A
Please scroll down to see the correct answer and solution guide.
Right Answer is: D
SOLUTION
According to given data, a circuit diagram can be drawn
Initially, there is no potential difference across the capacitor before closing the switch.
So that at the instant of closing the switch, circuit diagram can be redrawn as
Hence, at the instant of closing the switch (t = 0+) capacitor is short circuited, it is because capacitor maintains it’s previous voltage \(i.e.\;\left[ {{V_{\left( {{0^ - }} \right)}} = {V_{\left( {{0^ + }} \right)}}} \right]\)
∴ Current through the circuit can be calculated as
\(I = \frac{5}{{20}}\)
I = 0.25 A
