A long vertical wire carries a steady 15 A current. A pair of rails are horizont
ID: 1769230 • Letter: A
Question
A long vertical wire carries a steady 15 A current. A pair of rails are horizontal and are 0.3 m apart. A 14.6 (ohm) resistor connects points a and b, at the end of the rails. A bar is in contact with the rails, and is moved by an external force with a constant velocity of 0.5 m/s as shown. The bar and the rails have negligible resistance. At a given instant t1, the bar is 0.1 m from the wire, as shown. In Figure, at time t1, the induced current in A is:
A long vertical wire carries a steady 15 A current. A pair of rails are horizontal and are 0.3 m apart. A 14.6 (ohm) resistor connects points a and b, at the end of the rails. A bar is in contact with the rails, and is moved by an external force with a constant velocity of 0.5 m/s as shown. The bar and the rails have negligible resistance. At a given instant t1, the bar is 0.1 m from the wire, as shown. In Figure, at time t1, the induced current in ½A is:Explanation / Answer
Magnetic field due to long straight wire
B=uo*I/2pir =(4pi*10-7)*15/2pi*0.1
B=3*10-5 T
Induced emf
E=BLV =(2*10-5)*0.3*(0.5)
E=4.5*10-6 Volts
Induced current
I=E/R =(4.5*10-6)/14.6
I=0.3082 uA