• Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
    Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.

My friends homework assignment

Status
Not open for further replies.
D

Dman

Limp Gawd
Joined
Jun 14, 2001
Messages
170
I know you guys dont like doing other peoples homework, but um I want to try and help him out I am not great a circuits. Here is the problem:

In the section of circuit below, R1= 13.219 ohms, R2= 1.490 ohms, and the voltage difference Va-Vb= 4.900 V. The current i= 0.350 A. Find the current through R3.

It is like this:
Code: 
                        |----------<r2>-------|
----a---<r1>------                             ----------b
                        |---------<r3>--------|
 
To find R3
We know R = V/I, 4.9/0.35 = 14 ohms, this is the total resistance of the three resistors.

R1 + (R2 and R3 combined) = Rtotal, R1 - Rtotal = (R2 and R3 combined)
14 - 13.219 = 0.781

So the combined resistance of R2/R3 = 0.781 ohms

1/R2 + 1/R3 = 1/Rcombined
1/1.49 + 1/R3 = 1/0.781

R3 = 1.64 ohms to 3sf

To find the current through R3
Current splits inversely to resistance, ie the smaller resistor will have more current through it
1.64/(1.64+1.49) x 0.350 = 0.183

0.350 - 0.183 = 0.167 A to 3 sf
 
Status
Not open for further replies.
Back
Top