Find Current at Point T in Circuit

[nikolafmf]

Homework Statement

The circuit is given as in the attachment. All resistors have known resistance and the inner resistance of the ammeter in known. The current which is measured by the ammeter is known. What is the current at the point T?

Homework Equations

Ohm's law: V=IR. Also at each junction, I_in=I_out.

The Attempt at a Solution

Let R₀ be the resistance of the ammeter, I₁ be the current at the point T, I₂ be the current at resistor R₂ and I_A be the current at ammeter. It follows that I_AR₀=I₂R₂, from which I₂ follows. Then I₁=I₂+I_A.

That is what I think is true. But, given the values of resistances of all resistors which I didn't use in the calculation, I start to wonder if I miss something. Am I right or wrong?

 

[NascentOxygen]

You are right so far, but not yet finished. You should end up with something like

I_T = k.I_A where k is a value you determine

 

[nikolafmf]

You are right so far, but not yet finished. You should end up with something like

I_T = k.I_A where k is a value you determine

Isn't I_T=I₂+I_A? (conservation of charge at the junction)

 

[NascentOxygen]

Isn't I_T=I₂+I_A? (conservation of charge at the junction)

Correct. But we don't know I2 so eliminate it from the equation.

 

[nikolafmf]

Correct. But we don't know I2 so eliminate it from the equation.

But I₂=I_AR₀/R₂...