Study the following circuit diagram in fig. 5.320 and mark the correct options.

Options

A. The potential of point a with respect to point b in the figure when swithc S is open is - 6V.
B. The points a and b are at the same potential, when S is opened.
C. The charge flowing through switch S when it is closed is `54muC.`
D. The final potential of b with respect to ground when switch S is closed is 8V.

Answer

A, C

Explanation

When S is opened
`V_(c )-V_(a)=(18xx6)/(6+3)=12 V` or `V_(b) - V_(a) =12 -6 = 6V`
,
Charges flowing after S is closed:
`q_(1) =72 - 36 = 36muC, q_(2) = 36 -18 = 18muC`
Charges flowing through S after it is closed:
`36+18 = 54muC`
Final potential of b is 6V.