A=29 B=39 C=139 D=12 3. If q1=BnC, q2=-B/5 nC, q3= D nC are sitting at corners of the equilateral of side length D cm, What is the electrical potential at point at the center? What is potential energy of the system? (10 Points) 4. B electrons are distributed on circumference of the circle of radius R= D cm. What is the electric potential at center? What is the electric field at center? (10 Points) 5. If a = D cm, b = C cm, q = B nC, and Q=D nC in the figure, what is the potential difference VA - VB? (10 Points) 6. a. What is the equivalent capacitance of the combination shown by using C1=C2=C3=C4=C5=C6=D LF? (10 Points) b. Calculate the charge O stored in the circuit if it connected to 12 V battery in two open terminals? (5 Points) c. Calculate the total energy stored in the capacitor? (5 Points) 7. A capacitor, C, is (fully) charged by connecting it to a D Volt EMF and then is allowed to discharge through a 2 2 resistor as shown in the Figure. What is the current, I, in the circuit (in A) when the stored energy in the capacitor has dropped to 30% of its initial value? (10 Points) R = 20 8. If C1=C2=C3 =2 UF , calculate the equivalent capacitances of the two circuits shown in the figure. Are they the same? (10 Points)