Question

Short answer questions: a. The magnitude of the magnetic field at a distance R from a long straight wire is equal to B. At what distance will the magnitude of the magnetic field be equal to 3B? b. Two long parallel wires carry equal but opposite currents. Are there any points in space where the total magnetic field is equal to zero? If so, where? If not, why not? c. A simple loop circuit contains two sources, a resistive wire, and a switch. It is placed next to a long straight wire carrying a steady current. As soon as the switch is closed, the loop is suddenly pulled towards the long wire. Which source has a greater emf? Justify your answer.

Answer 1

B = uo*I/(2*pi*R)

3B = uo*I/(2*pi*R')

3*uo*I/(2*pi*R) = uo*I/(2*pi*R')

R' = R/3 <<<<-------------answer

b) No

c) e1 > e2