Calculating Time Constants for RC and RL Circuits | Simple Physics Homework Help

[jayz618]

Homework Statement

Calculate the time constants of the following circuits

I drew them in the attachment

Homework Equations

t=RC in a RC Circuit

t= L/R in a RL Circuit

The Attempt at a Solution

Im not sure if in the first one, I would simply add the two resistors and multiply the total by the Capacitance ?

If so, then it would be 45 k Ohm x 2 Micro Farads = 45000 Ohms x 2E-6 Farads = .09 Seconds


The second one, I calculated the value of the parralell resistors as 30 ohm x 80 ohm / 110 ohm = 21.81 Ohms

Then it would just be 50 milliHenries = .05 Henries / 21.81 Ohm = .0022 Seconds

 

[kuruman]

Correct.

 

[jayz618]

For the first one, it doesn't matter that the second resistor comes after the capacitor ?

 

[kuruman]

It doesn't matter. The resistors are in series. Whatever charges move through one resistor, have to go through the other.

 

[jayz618]

Cool, so I was correct on both attempts ? Good News




Thanks