# physics

posted by .

The figure below shows a collection of wires. The currents at the numbered points are: I1 = 2.4 mA right; I2 = 3.6 mA down; I3 = 0.60 mA right; I4 = 4.0 mA up; and I5 = 1.6 mA up.
i. imgur. com/SCyljHG. png
a. What is the current at point A (size and direction)?

b. What is the current at point B (size and direction)?

• physics -

We’ll use Kirchhoff’s Current Law: At any node (junction) in an electrical circuit, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node.

Node: I₁, I₂ and I₁₂ currents:
I₁+I₂-I₁₂= 0
I₁₂=I ₁+I₂ = 2.6+3.4=6 mA (to the right)
Node: I₁₂, I₃ and I(A) currents:
I₁₂ - I₃ + I(A)=0
I(A) =I₃-I₁₂= 0.6-6=- 5.4 mA =>upward
Node: I₃, I₄, I₅, I₆:
I₃+ I₄- I₅ + I₆=0
I₆=-I₃- I₄+ I₅=-0.6-4+1.6=-3 A=> to the right
Node: I(A), I₅ and I₇:
I(A)+I₅-I₇=0
I₇=I(A)+I₅=5.4+1.6=7 mA => to the right
Node: I(B), I₆ and I₇:
I₆ + I₇-I(B)0
I(B)= I₆ + I₇=3+7=10 mA (upward)

## Similar Questions

1. ### College Physics

Two long, straight, parallel wires 8.0 cm apart carry currents in opposite directions. Use the right-hand source and force rules to determine whether the forces on the wires are attractive or repulsive. a)Repulsive b)Attractive If …
2. ### physics

Two parallel wires in a horizontal plane carry currents I1 and I2 to the right. The wires each have a length L and are separated by a distance d. calculate the following where: I1 = 10A, I2 = 20A, d = 5mm, and L = 2m. What are the …
3. ### physics

The four wires that lie at the corners of a square of side a= 5.60 cm are carrying equal currents i= 1.80 A into (+) or out of (-) the page, as shown in the picture. Calculate the x-component of the force on a 1.0-cm long piece of …
4. ### Physics 2

The wire in the figure below carries a current of 13 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 26 A. Use Ampère's law to find the magnitude of the magnetic field …
5. ### Physics 2

The wire in the figure below carries a current of 13 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 26 A. Use Ampère's law to find the magnitude of the magnetic field …
6. ### Physics II

two perpendicular, long, straight wires, both of which lie in the plane of the paper. The current in each of the wires is I = 4.5 A. In the drawing dH = 0.13 m and dV = 0.48 m. Find the magnitudes of the net magnetic fields at points …
7. ### Physics 2

The wire in the figure below carries a current of 12 A. Suppose that a second long, straight wire is placed right next to this wire. The current in the second wire is 30 A. Use Ampère's law to find the magnitude of the magnetic field …
8. ### Physics

The figure below shows two current carrying wires and the directions of the currents they carry. The wires carry the following currents: I1 = 7.1 A and I2 = 8.9 A. Wire 1 is at (0, 5.8) mm; wire 2 is at (15.1, 0) mm; point P is at …
9. ### physics

The figure below shows two current carrying wires and the directions of the currents they carry. The wires carry the following currents: I1 = 12.5 A and I2 = 9.8 A. Wire 1 is at (0, 4.0) mm; wire 2 is at (13.3, 0) mm; point P is at …
10. ### physics

Two long, straight, parallel wires 10 cm apart carry currents in opposite directions. (a) Use the right-hand source and force rules to determine whether the forces on the wires are (1) attractive or (2) repulsive. Show your reasoning. …

More Similar Questions