Question

An 8.0-V battery is connected to an RC circuit (R = 19 Ω and C = 1.3 μF). If the capacitor is initially uncharged, what is the current in the circuit immediately after the connection is made?

Answer 1

0.42 A

Step-by-step explanation:

Note: Since the capacitor is initially uncharged, then the voltage across the capacitor immediately after connection is 0 V.

From ohm's law,

V = IR .................. Equation 1

Where V = Voltage, I = Current, R = Resistance of the resistor.

I = V/R ............. Equation 2

Given: V = 8.0 V, R = 19 Ω

Substitute into equation 2

I = 8/19

I = 0.42 A.

Note: Since both the resistor and the capacitor are connected in series, The current flowing through the the resistor is equal to the current flowing through the capacitor.

Hence, the current in the circuit = 0.42 A

Answer 2

O.421 A

Step-by-step explanation:

Immediately after the connection is made, there is no voltage across the capacitor (it is initially uncharged).

And since the circuit elements are connected in series with each other, current in the circuit is potential difference across divided by the resistance along the path. That is,

I = (Vs - Vc)/R

where Vs is the voltage from the voltage source = 8 V

Vc = Voltage across the capacitor = 0 V at this moment.

R = Resistance in the circuit = 19 ohms

I = 8/19 = 0.421 A