P26_084.PDF

84. (Third problem of Cluster )

(a) With the series pair C 2 and C 3 reduced to a single C =10 µ F capacitor, this becomes verysimilar

to problem 82. Noting for later use that q = q 2 = q 3 , and using notation similar to that used in

the solution to problem 82, we have

Q = q 1 + q

where Q = C 1 V bat = 400 µ C. Also, after switch S is closed,

V 1 = V

q 1

C 1

which yields 4 q 1 = q . Therefore,

Q = q 1 + 1

4 q 1

which gives the result q 1 = 320 µ C.

(b) We use q 2 = q 3 = 4 q 1 to obtain the result 80 µ C.

(d) (e) and (f) Eq. 26-1 yields

V = q

8 . 0V for C 1

5 . 3V for C 2

2 . 7V for C 3

C =