An infinite straight wire carries a current I that varies with time as shown abo
ID: 2009524 • 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 I1 = 6 A at t = t1 = 18 s, remains constant at this value until t = t2 when it decreases linearly to a value I4 = -6 A at t = t4 = 38 s, passing through zero at t = t3 = 30.5 s. A conducting loop with sides W = 33 cm and L = 80 cm is fixed in the x-y plane at a distance d = 47 cm from the wire as shown.
1) What is the magnitude of the magnetic flux through the loop at time t = t1 = 18 s?
2) What is 1, the induced emf in the loop at time t = 9 s? Define the emf to be positive if the induced current in the loop is clockwise and negative if the current is counter-clockwise.
3) What is 2, the induced emf in the loop at time t = 20 s? Define the emf to be positive if the induced current in the loop is clockwise and negative if the current is counter-clockwise.
4) What is the direction of the induced current in the loop at time t = t3 = 30.5 seconds?
5) What is 4, the induced emf in the loop at time t = 34.25 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) Flux= Mo*I*W*ln((d+a)/d) 2) E1= Flux/time time being the time of the first problem(t=18s for your problem) 3,4) 0