2) A long vertical wire carries a steady 70 A current. As shown in the figure, a

Question

2) A long vertical wire carries a steady 70 A current. As shown in the figure, a pair of horizontal rails are 0.20 m apart. A 20-2 resistor connects points a and b, at the end of the rails. A bar is in contact with the rails, and is moved by an external force with a constant horizontal velocity of 0.90 m/s to the right, as shown. The bar and the rails have negligible resistance. At the instant that the bar is 0.20 m from the wire, what are the induced current in the resistor and its direction through the resistor? (0-4 × 10-7 T·m/A) +0.20 m v = 0.90 m/s 70 A 20 0.20 m

Explanation / Answer

Magnetic field due to long straight wire is given by

B=uoI/2pir =(4pi*10-7)*70/2pi*0.2

B=7*10-5T

Induced emf is

E=BLv=(7*10-5)*0.2*0.9

E=1.26*10-5Volts

induced current is

I=E/R =(1.26*10-5)/20

I=6.3*10-7 A or 0.63mA

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

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