The correct options are
A The current through resistor
R3 at the moment the switch closed is zero
B The current through resistor
R3 a long time after the switch closed is
5 A C The ratio of current through
R1 & R2 is always constant
D The maximum charge on the capacitor during the operation is
5 μC
Given,
E=10 V ; C=1.0 μFR1=2 Ω ; R2=2 Ω ; R3=1 Ω
Just after closing the switch, capacitor will act as wire. Thus, current through the resistor
R3 is zero.
After closing the switch at
t=∞, the capacitor will act as an open circuit.
∴ Current through the battery is,
I=VR3+R1R2R1+R2=101+2×22+2=5 A
∴ VAB=iR3=5 V
The maximum charge on the capacitor is,
Q=CV=1.0 μF×5 V=5 μC
Since,
R1 & R2 are in parallel,
I1R1=I2R2
I1I2=R2R1=constant
Hence, all four options are correct.