A solid rectangular metal bar of length L and width W is dragged at speed v through a region of uniform magnetic field B as shown. What is the direction (left/right/top/bottom/in/out/zero) of the magnetic force on the conduction electrons in the bar? а. left b. The magnetic force will lead to a charge separation in the bar. Which is true? The left end is positive and the right is negative. The left end is negative and the right is positive. The bottom end is negative and the top is positive. The bottom end is positive and the top is negative. The charge separation will generate an electric field inside the bar. The electric field will grow until the electric and magnetic forces on the charges balance. What is the magnitude and direction of the electric field inside the bar? Give magnitude E in terms of B , v , L and/or W. Think: we've done something similar before. с. Fm = Fe qv B = q E => E = v B direction is upwards d. The electric field will generate a voltage difference across the bar. What is true of the voltage difference? The left end is at a higher voltage than the right. The right is at a higher voltage than the left. The bottom end is at a higher voltage than the top. The top is at a higher voltage than the bottom. Write the magnitude of the voltage difference in terms of B, v, L and/or W. Hint: the electric field is uniform so that voltage difference is easy to find. е. AV = BL v

A solid rectangular metal bar of length L and width W is dragged at speed v through a region of uniform magnetic field B as shown. What is the direction (left/right/top/bottom/in/out/zero) of the magnetic force on the conduction electrons in the bar? а. left b. The magnetic force will lead to a charge separation in the bar. Which is true? The left end is positive and the right is negative. The left end is negative and the right is positive. The bottom end is negative and the top is positive. The bottom end is positive and the top is negative. The charge separation will generate an electric field inside the bar. The electric field will grow until the electric and magnetic forces on the charges balance. What is the magnitude and direction of the electric field inside the bar? Give magnitude E in terms of B , v , L and/or W. Think: we've done something similar before. с. Fm = Fe qv B = q E => E = v B direction is upwards d. The electric field will generate a voltage difference across the bar. What is true of the voltage difference? The left end is at a higher voltage than the right. The right is at a higher voltage than the left. The bottom end is at a higher voltage than the top. The top is at a higher voltage than the bottom. Write the magnitude of the voltage difference in terms of B, v, L and/or W. Hint: the electric field is uniform so that voltage difference is easy to find. е. AV = BL v