0 resistance wire in parallel circuit

[ehrenfest]

In question 1 b at the following site:

http://ocw.mit.edu/NR/rdonlyres/Physics/8-02Electricity-and-MagnetismSpring2002/6D148C87-C69B-44B6-AECA-CB9D875E0F40/0/exam2.pdf

I am having trouble with 1b. At the junction right after R1, why does the current go only up and not left when the upper path has zero resistance? Is there a law that says current always travels in the path of least resistance?

 

[learningphysics]

In question 1 b at the following site:

http://ocw.mit.edu/NR/rdonlyres/Physics/8-02Electricity-and-MagnetismSpring2002/6D148C87-C69B-44B6-AECA-CB9D875E0F40/0/exam2.pdf

I am having trouble with 1b. At the junction right after R1, why does the current go only up and not left when the upper path has zero resistance? Is there a law that says current always travels in the path of least resistance?

What is the voltage across the inductor in part b?

 

[malawi_glenn]

Yes current always takes the path with the smallest resistance.

 

[learningphysics]

You can also calculate the current in R2. Since current is finite and the resistance across the inductor is 0 in part b... the voltage across the inductor is I3*0=0. Hence the voltage across R2 is 0. I2=0/R2 = 0. So the current through R2 is 0.

 

[ehrenfest]

I see. Thanks.