At time t=0, a battery of 10 V is connected across points A and B in the given circuit. If the capacitors have no charge initially, at what time (in seconds) does the voltage across them beocme 4V? `[Take : In 5 = 1.6, In3 = 1.1]`.
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Answer

B

Explanation

The equivalent circuit is shown in the figure.
`R = 1MOmega, 4muF`

`:. The time constant `tau` = RC = 4 sec`
The potential across `4muF` capacitor at any time 't' is given as
`V = V_(00 [ 1-e^(-t/tau)] 4 = 10 [1-e^(t/4)] rArr t = 2sec` .