Kirchhoff's law: Find the current I3 through the Amp meter

AI Thread Summary
The discussion focuses on solving a circuit using Kirchhoff's laws, specifically finding the current I3 through an amp meter. The initial equations for the upper and lower loops were adjusted after identifying an error related to an extra resistor. The corrected equations led to the calculation of I3 as 0.336 A, with subsequent values for I1 and I2 determined as 2.43 A and 2.09 A, respectively. However, a verification of Kirchhoff's Voltage Law indicated a discrepancy, suggesting that the results could be more accurate with slight adjustments. The final values for I2 and I3 were confirmed to remain consistent despite the need for more precise calculations for I1.
skibidi
Messages
10
Reaction score
0
Homework Statement
Find the current I3,I2, and I1 through the Amp meter.
Answer in units of A.
Relevant Equations
I used the Junction Rule - I3= I1+I2
I separated the circuit into parts- upper and lower

For the upper loop I wrote: -14-2I1-3.4I3-I2 = 0
For the lower loop I wrote 16-2.9I2+3.4I3-5.4I2 = 0

I solved for I1 and I2 separately and plugged it into the junction rule and solved for I3.

I may have got it wrong because of the incorporation of the extra resistor in the upper loop and lower loop and solved incorrectly.

Utexas.png
 
Last edited by a moderator:
Physics news on Phys.org
Correction for the problem after i found I3 correctly now.

The correct equation is now -14+3.3(I1)+3.4(I3)+2(I1)= 0 for the upper loop and
-16+5.3(I2)-3.4(I3)+2.9(I2) = 0 for the bottom loop. Once you separate variables, I2 = stuff and I1 = stuff, you can use the junction rule I1 = I2+I3 and rearrange to get I1-I2=I3. Plug it in and you should get I3 = 0.336A
 
Use I3 to get I2 and I1 since you have separate equations for them already -

I1 = -3.4(I3)+14/5.3 and I2 = 3.4(I3) +16/ 8.2

I1 = 2.43 A , I2 = 2.09 A
 
If anyone else sees this, can you verify that my explanation is correct since I was able to get the correct answers on my own.
 
## \text { The explanation is correct, but the result can be more accurate. } ##

## 3,3 \Omega \cdot 2,43 A + ( - 14 ) V + 2 \Omega \cdot 2,43 A + 3,4 \Omega \cdot 0,336 A = ##
## = 8,0058 V – 14 V + 4,852 V + 1,1424 V = ##
## = 0,0214 V \neq 0 V ##
## \text { It is hard to say that Kirchhoff Voltage Law is satisfied for the upper loop because it is hard to say that } 0,0214 V \text { is equal to } 0 V \text { . } ##
## \text { The more accurate result can be got rounding the value of } I _ 1 \text { to } 2,426 A \text { instead of } 2,43 A \text { . } ##
## \text { Values of } I _ 2 \text { , which is } 2,090 A \text { , and } I _ 3 \text { , which is } 0,336 A \text { , can remain the same. } ##
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top