DC circuit, find current and potential

[sabak22]

https://www.physicsforums.com/attachments/39765

a) Calculate the current through the 5Ω resistance. Use '+' sign for the current directed from right to left, and '-' sign if the current flows from left to right.

b) The magnitude of the potential at 'a' is?


Please help me with the two questions above. I have tried to used the Kirchoff's law. but it doesn't seem to work for me. Thank you in advance!

(clicK on the picture to view the circuit)

 

[vk6kro]

https://www.physicsforums.com/attachments/39765

a) Calculate the current through the 5Ω resistance. Use '+' sign for the current directed from right to left, and '-' sign if the current flows from left to right.

b) The magnitude of the potential at 'a' is?


Please help me with the two questions above. I have tried to used the Kirchoff's law. but it doesn't seem to work for me. Thank you in advance!

(clicK on the picture to view the circuit)

You would really have to show your attempt at using Kirchoff's Laws, including the equations and a diagram showing the currents and voltages referred to in the equations.

Without that, we would have to just do the problem for you and that is against the rules here and also wouldn't do you any good.

 

[sabak22]

here are my attempts:

First i made 4 different loops. each one of them looking like this by using Kirchoff's current law:

A) 19-9I3-6I4+7-5I1=0
B) 7-5I1-16I2=0
C) 7-5I1+19-9I3-6I4=0
D) 19-9I3-6I4+16I2=0

But now I feel like I am stuck I don't know what to do. I don't even know if I am on the right track or not. I need help

 

[vk6kro]

You can combine the 9 ohm and 6 ohm resistors to get 15 ohms. This will cut down on the typing a bit.

Try using two currents. One going right from point "a" and one going down from point "a". The one through the 7V battery can be derived from these two currents.

Modify the first diagram to show the new currents and the polarities of the voltages across the resistors.

 

[DeeNos]

I would be happy to assist you with your questions regarding the DC circuit and finding current and potential.

a) To calculate the current through the 5Ω resistance, we can use Ohm's Law which states that the current (I) is equal to the voltage (V) divided by the resistance (R), or I = V/R. In this circuit, the voltage is provided by the battery, which has a voltage of 12V. Therefore, the current through the 5Ω resistance is 12V/5Ω = 2.4A. To determine the direction of the current, we can use the passive sign convention which states that current flows from higher potential to lower potential. In this case, since the battery is providing the voltage, the current flows from right to left, so we can use the '+' sign to represent the direction of the current.

b) To find the potential at point 'a', we can use the voltage divider rule which states that the potential at a point in a circuit is equal to the voltage of the source multiplied by the ratio of the resistance of that point to the total resistance in the circuit. In this case, the potential at point 'a' can be calculated as follows: V(a) = 12V x (5Ω/(5Ω+10Ω)) = 4V. This means that the potential at point 'a' is 4V.

I hope this helps to answer your questions and understand the concepts better. If you have any further questions, please do not hesitate to ask. Keep exploring and learning about circuits!