An infinite straight wire carries a current I that varies with time as shown abo
ID: 2251176 • 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 = 4.9 A at t = t1 = 19 s, remains constant at this value until t = t2 when it decreases linearly to a value I4 = -4.9 A at t = t4 = 32 s, passing through zero at t = t3 = 28 s. A conducting loop with sides W = 22 cm and L = 66 cm is fixed in the x-y plane at a distance d = 41 cm from the wire as shown.
1) What is the magnitude of the magnetic flux ? through the loop at time t = t1 = 19 s?
2) What is ?1, the induced emf in the loop at time t = 9.5 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 ?4, the induced emf in the loop at time t = 30 s? Define the emf to be positive if the induced current in the loop is clockwise and negative if the current is counter-clockwise.
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 = 4.9 A at t = t1 = 19 s, remains constant at this value until t = t2 when it decreases linearly to a value I4 = -4.9 A at t = t4 = 32 s, passing through zero at t = t3 = 28 s. A conducting loop with sides W = 22 cm and L = 66 cm is fixed in the x-y plane at a distance d = 41 cm from the wire as shown. 1) What is the magnitude of the magnetic flux ? through the loop at time t = t1 = 19 s? What is ?1, the induced emf in the loop at time t = 9.5 s? Define the emf to be positive if the induced current in the loop is clockwise and negative if the current is counter-clockwise. What is ?4, the induced emf in the loop at time t = 30 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)the magnetic flux is
O = B x A
where B = u_o x N x I1,u_o = 4pi x 10^-7 T.m/A,N = 1,I1 = 4.9 A and A = W x L
2)the induced emf is
e = L x (dI/dt)
where L = (u_o x N^2 x A/L),dI is change in current and dt = 9.5 s
3)the induced emf is
e1 = L x (dI1/dt1)
where dI1 is change in current and dt1 = 30 s