Answer to Question #102694 in Electricity and Magnetism for Sofiumer

Question

Two capacitors are connected in series c1=1f , v1=10v and c2=3f , v2= 20f find total voltage of the system 30 is not the answer


Answer 1

Two capacitors are connected in series:

$q_1=C_1V_1=(1)(10)=10\ C$ $q_2=C_2V_2=(3)(20)=60\ C$

Total charge:

$q=q_1+q_2=10+60=70\ C$

Capacitance:

$C=\frac{C_1C_2}{C_1+C_2}=\frac{(1)(3)}{1+3}=0.75\ F$

Total voltage of the system:

$U=\frac{q}{C}=\frac{70}{0.75}=93. 3\ V$