Answer:
A) 1.6 s
Explanation:
Given that
V = 60 V,
VL = 24 V
R = 24 ohm
L = 42 H
We know that time constant λ given as
λ = L / R = 42 / 24 = 1.75
We know that voltage at time t given as
[tex]V-V_L=V(1-e^{-\frac{t}{\lambda}})[/tex]
Now by putting the values
[tex]60-24=60(1-e^{-\frac{t}{1.75}})[/tex]
[tex](1-e^{-\frac{t}{1.75}})=0.6[/tex]
t/1.75 = ln (2.5)
t/1.75 = 0.916
t = 1.6 s
So answer is A) 1.6 s
