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circuit question help

hi, any help with question 3 from this link would be appreciated!

https://www.bpho.org.uk/Papers/R0/Round_0_Sample_Questions_2025.pdf

Reply 1

Eimmanuel

Study Forum Helper

Original post

by farhan999

hi, any help with question 3 from this link would be appreciated!

https://www.bpho.org.uk/Papers/R0/Round_0_Sample_Questions_2025.pdf

Do you know Kirchhoff's circuit rules?

If yes, how do you write the voltage rule and current rule for this circuit?

Reply 2

farhan999

Original post

by Eimmanuel

Do you know Kirchhoff's circuit rules?
If yes, how do you write the voltage rule and current rule for this circuit?

I think for KCL then if we say the left branch has current I1 and right branch has current I2, and for both the current goes anti-clockwise, then I2 = I1 + I, so I = 1/2, but if we say that on the left side the current is going clockwise and on the right it's going anticlockwise, then we get I = I2 + I1, and then wouldn't we get I = 1.5? I'm a bit confused as to what signs I should be using and where

Reply 3

Eimmanuel

Study Forum Helper

Original post

by farhan999

It does not matter which direction you choose. The final answer will tell you if you have chosen the correct direction.

If you choose both I1 and I2 to go in an anticlockwise direction, I2 = I1 + I, and the final answer(s) is/are negative then you have assumed the wrong direction for the respective currents.