10 A 5F a 7F and an unknown capacitorCX are connected in ser

10) A 5-F, a 7-F, and an unknown capacitorCX are connected in series between points a and b. What do you know about the equivalent capacitance Cab between a and b? (There could be more than one correct choice.) Please list all possible answers AND explain.

A) Cab < 5 F

B) Cab > 12 F
C) 5 F <Cab < 12 F

D)Cab<CX
E) 5 F <Cab < 7 F

Solution

Here,

for the capacitors in series

1/Cab = 1/C1 + 1/C2 + 1/CX

1/Cab = 1/5 + 1/7 + 1/CX

hence , the equivalent capacitor Cab will be smaller than all the capacitors

hence ,the correct options are

A) Cab < 5 F

D)Cab<CX