A circular coil enclosing an area of 98 cm2 is made of 199 turns of copper wire.
ID: 1455213 • Letter: A
Question
A circular coil enclosing an area of 98 cm2 is made of 199 turns of copper wire. The wire making up the coil has resistance of 4.0 , and the ends of the wire are connected to form a closed circuit. Initially, a 1.2 T uniform magnetic field points perpendicularly upward through the plane of the coil. The direction of the field then reverses so that the final magnetic field has a magnitude of 1.2 T and points downward through the coil. If the time required for the field to reverse directions is 0.16 s, what average current flows through the coil during that time?
Explanation / Answer
The area is A = 98 x 10^-4 m².
The change in magnetic flux is
= AB = (98 x 10^-4 m²) x (1.20 T - (- 1.20 T))
= (98 x 10^-4 m²) x (1.20 T + 1.20 T))
= 0.0235 Wb
The average induced emf is
|| = N / t
= (199 turns x 0.023 Wb) / (0.160 s)
= 28.60 V
The average current is
I = / R =28.60 V / 4.00 = 7.15 A
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.