Question

Find the charge capacitor C in the following circuit

Answer 1

Answer :

Voltage of battery = 12V

Capacitance of capacitor = 2μF

We have to find charge on capacitor under steady state condition$.$

★ Remember :

• At steady state (t = ∞), no current flow in capacitor containing branch.

In order to find charge on capacitor, we need to find potential difference across capacitor containing branch.

Let's find equivalent resistance. We will not consider that 2Ω resistor (in middle branch) as no current flow in that resistor at t = ∞

At t = ∞ : Req = 2 + 6 = 8Ω

Current flow in circuit :

• I = V/Req = 12/8 = 1.5A

Let's find pd across 6Ω resistor,

• V' = IR = 1.5×6 = 9 volts

We know that, pd across each resistor remains same in parallel.

∴ Pd across capacitor branch also will be 9 volts.

★ Charge on capacitor :

• Q = CV' = 2 × 9
• Q = 18 μC