Question

how to get the voltage if all you have is R6 which is 60 ohms and I6 214.57 in combined parallel and series circuits. :)

Answer 1

Answer:

For a DC L-R circuit, current in the inductor grows as per below relationship,

I(t)=I

0

(1−e

−t/τ

)

Here, I

0

=V/R=12/6=2A, is the steady-state current through the circuit.

τ=L/R=8.4m/6=1.4ms, is the time constant.

So, I(t)=1A⟹2(1−e

−t/1.4m

)=1

⟹e

−t/1.4m

=0.5

Taking logarithm of both sides,

−t/1.4m=−0.693⟹t=0.97ms≈1ms

Option D is correct.