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Consider the combination of capacitors in the figure below. (Let C 1 = 20.0 F an

ID: 2136146 • Letter: C

Question

Consider the combination of capacitors in the figure below. (Let C1 = 20.0 F and C2 = 2.00 F.)

4.00-F capacitor     C 2.00-F capacitor    
C 20.0-F and 8.00-F equivalent capacitor    
C Consider the combination of capacitors in the figure below. (Let C1 = 20.0 mu F and C2 = 2.00 mu F.) Find the equivalent single capacitance of the two capacitors in series and redraw the diagram (called diagram 1) with this equivalent capacitance. In diagram 1 find the equivalent capacitance of the three capacitors in parallel and redraw the diagram as a single battery and single capacitor in a loop. Compute the charge on the single equivalent capacitor. Returning to diagram 1, compute the charge on each individual capacitor. Does the sum agree with the value found in part (c)? What is the charge on the 20.0-mu F capacitor and on the 8- mu F capacitor? Compute the voltage drop across the 20.0-mu F capacitor. Compute the voltage drop across the 2.00-mu F capacitor.

Explanation / Answer

a) C18 = 20 x 8 / (20 + 8) = 5.71 uF

b) Ceq = 4 + 2 + 5.71 = 11.71 uF

c) Q = CV = 11.71 x 10-6 x 36 = 421.71 uC

d) Q4 = 36 x 4 =144 uC
Q2 = 72 uC
Q18 = 5.71 x 36 = 205.56 uC
netQ = 421.66
yes , equal.

e) on 20   = 8 x 205.56 / 28 = 58.73 uC
on 8 = 20 x 205.56 / 28 = 146.83 uC

f) V20 = 58.73/20 = 2.94 V

g_ V8 = 146.83/8 = 18.35