A loop of wire of radius a = 50. mm has an electrical resistance R = 0.031 ? . T

Question

A loop of wire of radius a = 50. mm has an electrical resistance R = 0.031 ? . The loop is initially inside a uniform magnetic field of magnitude B0 = 1.3 T parallel to the loop's axis. The magnetic field is then reduced slowly at a constant rate, which induces a current I = 0.20 A in the loop. How long does it take for the magnitude of the uniform magnetic field to drop from 1.3 T to zero?

Part B: What is the direction of the induced current in the wire shown in the picture?

A. Clockwise

B. Counterclockwise

* I AM MOST CONCERNED FOR THE ANSWER FOR PART B. IS IT CLOCKWISE OR COUNTERCLOCKWISE?*

Explanation / Answer

e = RI = .031 x .20 = .0062 V

e = d phi / dt

phi = B.A

e = d (B.A) /dt

e = A dB/dt

A = pi r^2 = pi x ((50/2) x 10^-3)^2 = 1963.49 x 10^-6 m^2

.0062 = .001963 x 1.3 / t

t = 0.41 sec

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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