An infinite straight wire carries a current I that varies with time as shown abo
ID: 1456118 • Letter: A
Question
An infinite straight wire carries a current I that varies with time as shown above. It increases from 0 at t = 0 to a maximum value l_1 = 2.7 A at t = t_1 = 14 s, remains constant at this value until t = t_2 when it decreases linearly to a value l_4 = -2.7 A at t = t_4 = 25 s, passing through zero at t = t_3 = 22 s. A conducting loop with sides W = 36 cm and L = 76 cm is fixed in the x-y plane at a distance d = 36 cm from the wire as shown. What is the magnitude of the magnetic flux phi through the loop at time t = t_1 = 14 s? What is epsilon_1, the induced emf in the loop at time t = 7 s? Define the emf to be positive if the induced current in the loop is clockwise and negative if the current is counter-clockwise.Explanation / Answer
1) magnitude of magnetic flux = (2 * 10-7) * 2.7 * 0.36 * ln(1.12/0.36)
= 2.206 * 10-7 T. m2
2) induced emf = (2 * 10-7) * (2.7/14) * 0.36 * ln(1.12/0.36)
= - 1.575 * 10-8 V