In: Physics
Consider the circuit shown in the figure below where L = 4.80 mH and R2 = 420 ?.
Consider the circuit shown in the figure below whereL=4.80mHandR2=420?.
(a) When the switch is in position a, for what value of R1 will the circuit have a time constant of 15.1 s k?
(b) What is the current in the inductor at the instant the switch is thrown to position b?
a)time constant
τ =L/R
15.1*10-6 =4.8*10-3/R
R=317.88Ω
since R1 andR2 are in parallel
R=R1R2/(R1+R2)
317.88 =R1*420/(R1+420)
317.88R1+133509.6=420R1
102.12R1 =133509.6
R1 =1307.4Ω≈1.307KΩ
b)I=V/R =24/317.88 =7.55mA