Exam 2 Review: Circuits, Magnetism, Induction
Supplemental Instruction
IowaStateUniversity / Leader: / German
Course: / Phys 222
Instructor: / Dr. SoerenPrell
Date: / 04/01/2014

Introduction (15min)

  1. Write down any specific questions you may have of the material, quizzes, homework or previous exams. We will go over them after the introduction.
  1. Complete the following crossword puzzle

Please do not start the next section until you are indicated to do so

Part 1 (35min)

Please work individually for 25 min in the following multiple-choice problems

1)A material is placed inside a solenoid and the energy density of the magnetic field increases from 0.02J/m3 to 4000 J/m3. What type of material is this and what is the Km for this material? Remember B = KmBext

  1. Ferromagnetic, Km = 316
  2. Diamagnetic , Km = 0.0022
  3. Paramagnetic, Km = 447
  4. Ferromagnetic, Km = 447

2)Consider the sliding rod AB, which makes electrical contact with the U-shaped conductor shown to the right. This is located in a magnetic field pointing into the page. If the B field was suddenly increased, the rod would,

  1. Rotate clocwise
  2. Move to the left
  3. Move to the right
  4. Move outside the page (up)
  5. Remain stationary

3)An ion with a charge of +2e and velocity of 6.90x103 m/s enters a region of magnetic field (0.80T) and moves in a circular trajectory with diameter of 60.0 cm. What os the mass of this ion?

  1. 6.71x10-26 kg
  2. 3.33x10-27 kg
  3. 2.22x10-26 kg
  4. 1.12x10-26 kg
  5. 0.71x10-27 kg

4)A square loop of side 2cm and resistance 4Ω is located in a region of magnetic field perpendicular to the plane of the loop. The current on the loop at t=2s is

  1. 0.20 mA
  2. 0.40 mA
  3. 0.55 mA
  4. 0.70 mA
  5. 0.85 mA

5)The loop in the diagram carries a CCW current I, while the wire carries a downward current of 1.5 I. Determine the direction of the B field and which element has the most contribution to the B field created

  1. Out of the page, the wire loop
  2. Out of the page, the current wire
  3. Out of the page, equal contributions
  4. Into the page, equal contributions
  5. Into the page, the wire loop

6)Two particles with charge q > 0 move with identical speed but different direction along parallel paths at separated a distance d. When the particles are at the closest to each other, what is the magnetic force between them, and the direction?

  1. , attractive
  2. , repulsive
  3. , repulsive
  4. , attractive
  5. , repulsive

Please do not start working on Part 2 until you are indicated to do so

Part 2 (35 min)

Please work individually for 25 min in the following multiple-choice problems

1)Which of the following diagrams best represents the voltage diagram for an AC circuit containing an AC source (w > 3000 Hz), a resistor, an inductor (L = 5H) and a capacitor (C = 0.5 F) connected in series.

2)A circular coil of wires with 150 turns and a diameter of 4cm carries a current of 3A. This coil is placed in a magnetic field of 0.40T and at an angle of 60° with the axis of the coil. What is the torque on this coil?

  1. 0.49 N-m
  2. 0.20 N-m
  3. 1.96 N-m
  4. 0.11 N-m
  5. 0.28 N-m

3)The switch in the circuit nearby has been closed for a long time, and suddenly it is opened. At this moment, determine with point is at a lower potential

  1. “a” is at a lower potential
  2. “b” is at a lower potential
  3. Both points have the same potential
  4. We need to know the values for L and R to determine the answer

4)A rectangular loop is being moved out of a region of uniform magnetic field pointing into the page, as shown in the diagram nearby. The field has a strength of 0.02T, the dimensions of the loop are 20cm by 80cm, and the loop is moving at 50cm/s to the right. Determine the direction of the current and the magnitude of the EMF

  1. 4mV, CCW current
  2. 1mV, CW current
  3. 2mV, CCW current
  4. 4mV, CW
  5. 2mV, CW

5)(Continued )If the resistance of the loop is 0.02Ω, what is the B-field at point P, which is 0.05cm away from the short edge, and in the middle of the two longer sides?

  1. 3x10-3 T
  2. 3x10-7 T
  3. 3x10-5 T
  4. 3x10-4 T
  5. 3x10-6 T

6)Two parallel very long cables carry the same current in opposite directions and repel each other with a force-per-unit-length F. If both currents are doubled and the wire separation tripled, the new forces-per-unit-length will be,

  1. 6F

7)The wire loop in the figure (see next page) moves at a constant velovity to the right and goes through a region with constant magnetic field. Outside this area, the field is zero. Which diagram best describes the induced current, if CCW currents are taken as positive?

Please do not start working on Part 3 until you are indicated to do so

Closing (20 min)

What questions do you have about the exam material?

Next SI sessions before the exam:

  • Wednesday 5:10pm, 1160 Sweeney, Karl
  • Wednesday 7:10pm, 1051 Gilman, German

Good luck on the exam!