Insideyouriclicker insideyouriclicker

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Unformatted text preview: e a a nd to ta l num b e r o f turns . Ind uc to r B is twic e a s lo ng a s ind uc to r A L = µ0 n 2π r 2 z (1/2)2 2 C o m p a re th e ind uc ta nc e o f th e two s o le no id s A) LA = 4 LB B) LA = 2 LB C) LA = LB D) LA = (1/2) LB E) LA = (1/4) LB 50 40 30 20 10 0 WHAT ARE INDUCTORS AND CAPACITORS GOOD FOR? Inside your i­clicker Inside your i­clicker How to think about RL circuits Episode 1: How to think about RL circuits When no current is flowing initially: VL I=0 L I=V/R R L τ = L/R L/R R I VBATT At t = 0: I = 0 VL = VBATT VR = 0 (L is like a giant resistor) VBATT At t >> L/R: VL = 0 VR = VBATT I = VBATT/R (L is like a short circuit) τ = L/R L/R Preflight 4 In the circuit above, the switch has been open for a long time, and the current is zero everywhere. BB I At time t=0 the switch is closed. What is the current I through the vertical resistor immediately after the switch is closed? I (+ is in the direction of the arrow) A) I = V/R B) I = V/2R C) I = 0 D) I = ­V/2R E) I = ­V/R 40 Before: IL = 0 30 After: IL = 0 20 10 I = + V/2R 0 IL=0 RL Circuit (Long Time) Wh a t is th e c urre nt I th ro ug h th e ve rtic a l re s is to r a fte r th e s witc h h a s Wh b e e n c lo s e d fo r a lo ng tim e ? BB (+ is in th e d ire c tio n o f th e a rro w) A) I = V/R B) I = V/2 R C ) I = 0 D) I = ­V/2 R E) I = ­V/R + + After a long time in any static circuit: VL = 0 - - KVR: VL + IR = 0 How to think about RL circuits Episode 2: How to think about RL circuits When steady current is flowing initially: VBATT VL I=0 R L R L R I=V/R At t = 0: At t = 0: I = VBATT/R VR = IR VL = VR τ = L/R L/R τ = L/R L/R At t >> L/R: I = 0 VL = 0 VR = 0 Preflight 6 After a long time, the switch is opened, abruptly disconnecting the battery from the circuit. What is the current I through the vertical What is the current I through the vertical resistor immediately after the switch is opened? (+ is in the direction of the arrow) A) I = V/R B) I = V/2R C) I = 0 D) I = ­V/2R E) I = ­V/R circuit when circuit switch opened switch 35 L 30 25 IL=V/R C urre nt th ro ug h ind uc to r c a n...
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This document was uploaded on 02/13/2014.

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