Class 14 / Magnetic Fields / October 13th, 2017
  1. Two particles with charge q > 0 move with identical speeds but opposite directions along parallel paths separated by a distance d. What is the magnetic force between them when they are at the positions where they are closest to one another?
  1. , attractive
  2. , repulsive
  3. , attractive
  4. , repulsive
  1. A particle with positive charge q = 2C moves upward and enters a region where both a magnetic field and an electric field are present. The magnetic field has a magnitude of B = 4.0 x 10-4 T and points out of the page. The electric field has a magnitude of E = 0.1 N/C and points to the left. At what speed must the particle be moving if it is not deflected when it enters the region?
  1. 4.0 x 10-3 m/s
  2. 125 m/s
  3. 250 m/s
  4. 500 m/s
  5. The particle will be deflected to the left regardless of its velocity.
  1. The right edge of the circuit in the figure below extend into a 50 mT uniform magnetic field. What are the magnitude and direction of the net force on the circuit?
  1. 2.5 x 10-2 N to the right
  2. 2.5 x 10-2 N to the left
  3. 25 N to the right
  4. 25 N to the left
  5. 0
  1. An L-shaped metal machine part is made of two equal-length segments that are perpendicular to each other and carry a 4.50 A current as shown in the figure. This part has a total mass of 3.80 kg and a total length of 3.00 m, and it is in an external 1.20 T magnetic field that is oriented perpendicular to the plane of the part, as shown. What is the magnitude of the net magnetic field that the field exerts on the part?
  1. 22.9 N
  2. 8.10 N
  3. 11.5 N
  4. 32.4 N
  5. 16.2 N