Question

-9/viewform 7 puan The circuit below involves a 40 V battery, three resistors (5.00, 150, and 302), and three capacitors (0.02F, 0.04F, and 0.04F). The switch stays on position "a" for a long time to reach a stable state. At t=0 the switch is quickly toggled to position "b". What is the instantaneous current through the 15 Q resistor when t = 1.6 s? 15.02 30Ω w a 0.04F 40 V 0.02F 0.04F 5.00

Answer 1

car The 3 capacitores can be replaced by equivalent capacitor. connected in Series 80 Now Dk 0:04 F capacitors are equivalent of them cée 0.04x0.04 = 0.02 F 0:08 0.64 F 0.02 -0.04F ane NOW two two 0.02 F capacitor connected in parallel connectim, so the equivalent Capacitor = 0.02 +0.02 Toolf =0.04 F 0.02f4 0.02F Ceg Now when the switch is connected to point a for long time the equivalent capacitor got fully charged a voltage equal to supply voltage 40v. = 0.04x40 1.6 e. let at t-o, the switch is connected to b 152 the equivalent circuit is shown in the fig. at += 0, charge C Capacitor e=0.04.f is so = 1.60 e. 52 on the

+ charge & q is the let at omy time t 70. the capacitor and i is Circuit the current in the R=15+5 - VR = Rí :. Ve 올 - 20n From KVL (Kirchhoffe Voltage rule Rith Z zo R d4 तम R de 4 CR at q dq nt lat ER 2. upon integration In a-eng. ter t eR .t q =* 8o e er t da at Boire CR CR ey CR t the 2- e =% e tua

Now at t= 1.6 see 40 е. 0.04x20 20 - 2 =-2 e -0.27 A Negative sigor indicates eussent will decrease with time (16) į a = 0.27 A.