Please show step by step. Thank you!! A circular coil enclosing an area of 180 c
ID: 1550079 • Letter: P
Question
Please show step by step. Thank you!!
A circular coil enclosing an area of 180 cm2 is made of 190 turns of copper wire. The wire making up the coil has resistance of 7.0 , 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 0.40 s, what is the average current in the coil during that time?
Explanation / Answer
The area is A = 100 x 10^-4 m².
The change in magnetic flux is = AB = (180 x 10^-4 m²) x (1.20 T - (- 1.20 T)) = (180 x 10^-4 m²) x (1.20 T + 1.50 T)) = 0.0432 Wb
The average induced emf is || = N / t = (190 turns x 0.0432Wb) / (0.400 s) = 20.52 V
The average current is I = / R = 20.52 V / 7.00 = 2.9314 A