# Att0theswitchisclosed r1 v r2 i2 bb l r3 i2t0vr1r2r3

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Unformatted text preview: h inductor immediately AFTER switch is closed IS THE SAME AS the current through inductor immediately BEFORE switch is closed Immediately before switch is closed: IL = 0 since no battery in loop R3 Calculation Calculation The switch in the circuit shown has been open for a long time. At t = 0, the switch is closed. R1 V R2 BB L R3 IL(t=0+) = 0 What is the magnitude of I2, the current in R2, immediately after the switch is closed? V V V I2 = (A) (B) (C) (D) I2 = I2 = R2 + R3 R1 + R2 + R3 R1 We know IL = 0 immediately after switch is closed Immediately after switch is closed, circuit looks V like: I2 = R1 I= VR2 R3 R2 + R3 I R2 V R1 + R2 + R3 R3 Calculation Calculation The switch in the circuit shown has been open for a long time. At t = 0, the switch is closed. R1 V R2 I2 BB L R3 I2(t=0+) = V/(R1+R2+R3) IL(t=0+) = 0 What is the magnitude of VL, the voltage across the inductor, immediately after the switch is closed? R +R RR 3 VL = VL = 0 VL = V 2 VL = V (A) (B) (C) (D) (E)V R ( R2 +3 R ) R1 1 2 3 Kirchhoff’s Voltage Law, VL­I2 R2 ­I2 R3 =0 VL = I2 (R2+R3) VL = V ( R2 + R3 ) R1 + R2 + R3 VL = V R2 + R3 R1 + R2 + R3 Calculation Calculation The switch in the circuit shown has been open for a long time. At t = 0, the switch is closed. What is dIL/dt, the time rate of change of the current through the inductor immediately after switch is closed R1 V R2 BB L R3 VL(t=0+) = V(R2+R3)/(R1+R2+R3) dI L V R2 + R3 dI L dI L V R + R3 = = (A) (B) (C) (D) 2 =0 dt L R1 dt L R1 + R2 + R3 dt The time rate of change of current through the inductor (dIL /dt) = VL /L dI L V R2 + R3 = dt L R1 + R2 + R3 dI L V = dt L Follow Up Follow Up The switch in the circuit shown has been closed fo r a lo ng tim e . Wh a t is I2, the current through R2 ? (Positive values indicate current flows to the right)...
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