Magnetism Topics List

* This is not an exhaustive list (since each topic might have numerous problems associated with it), but it will serve as an excellent review for the Magnetism Test.

  • Magnet basics (poles, dipoles vs. monopole)
  • Understand what a compass is and where it points at any given moment.
  • Understand and be able to fully explain the meaning of a magnetic field line
  • Be able to figure out the direction that a compass would point (and would want to point) at different locations on the surface of the earth
  • Bar magnet magnetic field
  • Horsehoe magnet magnetic field
  • B-field between two magnets facing each other (N-N and N-S)
  • Magnetic characteristics of the earth
  • Which materials are magnetizeable
  • How to magnetize a non-magnetized material
  • How to de-magnetize an already magnetized material
  • Domain theory
  • Domains and electron spins
  • How to find (mag & dir) the magnetic force acting on a charged particle moving through a B-field.
  • When the particle won’t experience a force.
  • Why the particle might move in a circular path as well as the radius of the circular path.
  • How to find (mag & dir) the magnetic force acting on a current-carrying wire that is sitting in an external B-field.
  • How to find (mag & dir) the magnetic field around a current-carrying wire.
  • Be able to draw (with proper detail) the magnetic field around a current-carrying wire.
  • The magnetic field through a single loop of current-carrying wire.
  • The magnetic field through a solenoid.
  • The necessary parts of an electromagnet.
  • The reasons for inserting the “ferromagnetic core” inside an electromagnet.
  • Be able to identify and explain the purpose of each part of a DC motor (of either the single-loop PIZZA PADDLE variety or the multi-loop solenoid variety)
  • Be able to fully explain how a DC motor works (both varieties)
  • Be able to fully explain what the SRC does, why this is important, and how the motor would operate if the SRC failed to do its job).
  • Explain the difference between an AC motor and a DC motor (more than just AC vs. DC current!)
  • Be able to use all 3 Right-Hand Rules (RHRs) in various situtions.
  • What is NECESSARY to induce current in a loop of wire
  • Explain the 3 ways that current can be induced in a wire loop.
  • Explain which way best lends itself to use in a generator.
  • BE able to fully explain how a generator works as well as the differences between a DC motor and a DC generator.
  • Understand Lenz’s law and be able to figure out the direction of the induced current in multiple situations.
  • Be able to fully explain how a transformer works to change the output voltage & current.
  • Understand the difference between step-up and step-down transformers, including why the coils on the primary and secondary sides are different.
  • Fully explain why DC transformers do not work (in other words, why AC current is necessary)
  • HONORS only: Understand the difference between an IDEAL transformer and a non-ideal one, and how to calculate the efficiency of both kinds.

Equations to knowVocab list / Words to know

  • Domain
  • Pole
  • Monopole
  • Dipole
  • Flux
  • Hard magnetic material
  • Soft magnetic material
  • Ferromagnetic material
  • Permeability of Free-Space
  • Induced magnetism
  • Solenoid
  • Electromagnet
  • Source
/
  • Brush
  • Split-Ring Commutator
  • Slip-Rings
  • Transformer
  • Primary Coil
  • Secondary Coil
  • Primary Voltage (Current)
  • Secondary Voltage (Current)
  • Step-Up
  • Step-Down
  • Charge on a proton
  • Charge on an electron
  • Prefixes (mT, T, nT)

EXHAUSTIVE (and exhausting ) RIGHT-HAND RULE PRACTICE PAGES

  1. Given the battery combination below (with the compass either above or below the wire section AB), indicate (with a new arrow) the direction that the compass needle will deflect.
  1. Given the current carrying wires shown below, indicate the direction of the magnetic field at each of the lettered points (left, right, up, down, etc).

3. Given each set of two current carrying wires below, describe the net magnetic field at each lettered point. You may assume that the current flow in each wire has the same magnitude.

4. For the current-carrying conductors shown (with their magnetic fields), indicate the direction of CONVENTIAL CURRENT in each wire.

  1. Four current-carrying wires are shown below. The direction of the ELECTRON FLOW is shown. Draw the magnetic field lines around each one, including the appropriate “x” and “dot” markings.
  1. Draw the magnetic field generated around the single loop and around the SOLENOID (coiled wire) below.

7. For each electromagnet shown, label the appropriate ends of the nail as North (“N”) and SOUTH (“S”).

a)b)

c)d)

8. Two wires are shown below. One crosses over the top of the other. The directions of the CONVENTIONAL CURRENT in each wire is also shown. Which quadrants (I, II, III, or IV) have “constructive interference” of the fields (ie. the fields add together because they are in the same direction). Which quadrants have “destructive interference” (ie. the fields act against each other because they are in opposite directions). Label the quadrants as “C” or “D” for Constructive or Destructive.

a)b)c)

9. For each picture below, draw an arrow (labeled “I”) to depict the direction that the conventional current will flow through the loop of wire when the magnet is moved in the given direction.

a)b)

c)d)

10. Each picture below, a loop of wire is moving through a given magnetic field. Draw an arrow (labeled e-) to depict the direction that the electrons will move through the wire.

a)b)

c)d)

e)f)

11. In each picture below, either the magnet OR the coil (with a nail inside) will be moving. Indicate using an arrow labeled “I”, the direction of the induced conventional current that will be caused by the given movement.

a)b)

c) d)

e) f)

12. For each question below, find the direction of either 1) the motion of the charged particle, 2) the magnetic field, or 3) the magnetic force OR find the charge of the particle (whichever is unknown).

Charged particle’s sign: / -
Motion direction: / East
Dir. of Magnetic Field: / South
Dir. of Magnetic Force
/ Charged particle’s sign: / +
Motion direction: / North
Dir. of Magnetic Field:
Dir. of Magnetic Force / West
Charged particle’s sign: / -
Motion direction: / North
Dir. of Magnetic Field: / Upward
Dir. of Magnetic Force
/ Charged particle’s sign:
Motion direction: / South
Dir. of Magnetic Field: / East
Dir. of Magnetic Force / Upward
Charged particle’s sign: / -
Motion direction: / North
Dir. of Magnetic Field: / South
Dir. of Magnetic Force
/ Charged particle’s sign: / +
Motion direction: / Downward
Dir. of Magnetic Field: / East
Dir. of Magnetic Force
Charged particle’s sign:
Motion direction: / South
Dir. of Magnetic Field: / Upward
Dir. of Magnetic Force / East
/ Charged particle’s sign: / -
Motion direction:
Dir. of Magnetic Field: / North
Dir. of Magnetic Force / East

13. What is the direction of the force felt by each point shown below (up, down, or none).

14. If the loop is turned in the direction shown, which wire (A or B) will current travel OUT of.