Kirchhoff's Rule: Solving Two Equations

[soupastupid]

Homework Statement

write two independent equations using kirchhoff rule to describe the circuit.

Homework Equations

V=IR
Emf = IR

The Attempt at a Solution

The answer is
emf2 -I1R3-I2R2-I1R1 = 0
(ok i have questions here: why is it I1R1? shouldn't it be I4R1?)
and
emf1-I3R2+I2R2 = 0

(my question here is why is it +I2R2, why wouldn't u put -I2R2? or does it depend on which way you set up current through R2?)

 

[cepheid]

(ok i have questions here: why is it I1R1? shouldn't it be I4R1?)

There is no I4 that I can see. In any case, R1, emf2, and R3 are all in series, so the current has to be the same through all of them (and that current is I1 in this diagram)

(my question here is why is it +I2R2, why wouldn't u put -I2R2? or does it depend on which way you set up current through R2?)

When you go around the loop, you're moving across the resistor from bottom to top, which is the opposite direction from the direction of the current through that resistor. The current flows from top to bottom, which means that the top side is more positive than the bottom side. So if you move from bottom to top, you gain voltage.