Two long, straight, parallel wires are 1.0 m apart, as in the figure. The right

Question

Two long, straight, parallel wires are 1.0 m apart, as in the figure. The right wire carries a current I_1 of 12 A into the plane of the paper, (a) What must be the magnitude and direction of the current I_2 for the resultant field at point P to be zero? (r_2p = 0.20 m) A bar magnet with magnetic dipole moment = 0.5 A m^2 is oriented 30^degree from earth's magnetic field direction (B_e, = 2.5 times l0^-5 T). What torque does the bar magnetic in the figure, a conducting rod lies on two rails and completes a circuit when the switch is closed. When the switch is closed, the current flowing in the rod will be subject to the magnetic fields produced by the upper and lower rails whose fields can be approximated by those of long straight currents, (a) Consider this situation and determine the magnetic force direction on the rod. (b) If the emf is reversed in the circuit, what then is the magnetic force direction on the rod?

Explanation / Answer

Magnetic Field due to current carrying wire, B = (uo*i)/(2*r)
I1 = 12.0 A
r12 = 1.0 m
r2p = 0.2 m

For resultant field to be zero at point P,
(uo*I1)/(2*(r12+r2p) ) =  (uo*I2)/(2*r2p)
I1/(r12+r2p) = I2/r2p
12 / (1.0 + 0.2) = I2/0.2
I2 = 2.0 A
Dircetion of the current, I2 = out of the page !!

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.