- #1
fluidistic
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Homework Statement
See picture for the problem.
1)Calculate the work done to move a charge a= 0.7 x 10 ^(-3)C from A to B, passing by R2.
2)The power dissipated in R3.
3)The current passing by R1.
2. Given equations
R1=R3=100 omhs, R2=200 ohms, R4=300 omhs.
e1=e3= 5 V, e2=10 V and e4=15 V.
The Attempt at a Solution
I realize that the problem is very simple if only I get the current passing through each branch of the circuit. However, applying Kirchhoff's law of voltage, I reach non sense.
More precisely, let i1 be the current passing through e3, let's suppose it in the clockwise direction. Let i3 be the current passing through the e1 branch, suppose its direction as down. Let i2 be the current passing through R3, anticlockwise.
Then I get, according to Kirchhoff's law of voltage:
[tex]\varepsilon _3 - \varepsilon _2 - \varepsilon _1 - i_1 R_2 -i_3 R_1=0[/tex] and [tex]\varepsilon _4 - i_2(R_3+R_4)- \varepsilon _1 - i_3R_1 =0[/tex].
From it I reach [tex]i_1= -20V+400 i_2[/tex]. Of course units cannot match so there's at least an error. But I don't know where. I don't see it in the arithmetic so I guess I've used wrongly Kirchhoff's law, but I don't see it...
Thanks for any help.