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A long straight wire carrying a current I is in the plane of a circular loop of

ID: 2005075 • Letter: A

Question

A long straight wire carrying a current I is in the plane of a circular loop of wire as shown. The current I is increasing. Both the loop and the wire are held in place by external forces. The loop has resistance 23 .

At one instant, the induced current in the loop is 90 mA. What is the rate of change of the magnetic flux through the loop at that instant? (in Wb/s)

A long straight wire carrying a current I is in the plane of a circular loop of wire as shown. The current I is increasing. Both the loop and the wire are held in place by external forces. The loop has resistance 23 omega. At one instant, the induced current in the loop is 90 mA. What is the rate of change of the magnetic flux through the loop at that instant? (in Wb/s)

Explanation / Answer

Current through loop, i = 90 mA = 0.09 A The resistance, R = 23 But v = iR = 0.09 * 23 = 2.07 volts The number of loops, n = 1 we have a formula for the emf,  v = n(d/dt) From the above equation we have d/dt = v/n = 2.07 /1 = 2.07 Wb/s