Question

What is the current I0 that flows through the resistor immediately after the switch is thrown? Express your answer in terms of any or all of the quantities q, R, and C.

Answer 1

Answer:

A capacitor with capacitance C is initially charged with charge q. At time t=0, a switch is thrown to close the circuit connecting the capacitor in series with a resistor of resistance R. (see image below)

What is the current I0 that flows through the resistor immediately after the switch is thrown? Express your answer in terms of any or all of the quantities q, R, and C.

Explanation:

charge on the capacitor,

q = CV

C is the capacitance of the capacitor

V is the voltage across the capacitor

$V = \frac{q}{C}$

Determine the current flowing through the resistor after the switch is thrown

According to Ohm’s law, current flowing through the resistor is ,

$I_0 = \frac{V}{R}$

V is the voltage across the resistor

R is the resistance of the resistor

since $V = \frac{q}{C}$

$I_0 = \frac{q}{RC}$

Current through the resistor immediately after the switch is thrown $I_0 = \frac{q}{RC}$