Question

Two long wires carrying currents are 0.1 m apart as shown below in the figure. The left wire has a current I_L= 9 A (into the page), while the right wire has a current I_R= 5 A (out of the page).

(Questions & diagram below.)

Answer 1

a) What is the magnitude of the magnetic field created by the left wire at the midpoint, C?
Express your answer using three significant figures. Answer in T.

b) What is the direction of the magnetic field created by the left wire at the midpoint, C?

c) What is the magnitude of the magnetic field created by the right wire at the midpoint, C? Answer in T.

d) What is the direction of the magnetic field created by the right wire at the midpoint, C?

e) What is the magnitude of the TOTAL magnetic field at the midpoint, C?

f) What is the direction of the TOTAL magnetic field at the midpoint, C?

g) You now place a 15 cm long wire at the midpoint, C, which has a current of 10 A OUT of the page. What is the magnitude of the force on this third wire? Answer in N.

h) You now place a 15 cm long wire at the midpoint, C, which has a current of 10 A OUT of the page. What is the direction of the force on this third wire?

Answer 2

Here's the diagram.

Answer 3

Okay, so I got these correct: b) down d) down f) down h) right

Answer 4

a) (4pi*10^-7)(9)/2pi(0.05)=3.6*10^-5

That was right.
Trying to do b) the same way... then e) is just adding a) and c) together.
I'm not sure about g), though.

Answer 5

c) (4pi*10^-7)(5)/2pi(0.05)=2*10^-5

Same concept, got that correct.

Answer 6

e) = a) + c)

= 2*10^-5

which is correct.

Can someone help me with g)??

Answer 7

g) is 8.4*10^-5

Got everything correct!