Multiple Choice Section

Choose the answer which best completes each of the following statements or answers
the following questions.
 
1.   What is the name for the region around a magnet where magnetic forces act?
       (1.) the north pole   (2.) a compass   (3.) the magnetic domain
       (4.) the magnetic field

2.   Why does the needle of a compass always point north?
       (1.)  It has been electronically programmed to do so.
       (2.)  It aligns with Earth's magnetic field lines.
       (3.)  It is attracted to a large metal pole at the top of Earth.
       (4.)  There are more magnetic materials in northern regions of Earth.

3.   Explain how magnetic domains form.
      (1.)  Forces within magnetic materials align magnetic poles of small atom groups.
      (2.)  They form when a permanent magnet induces magnetism in a nail.
      (3.)  They form when a piece of iron is inserted into a coiled wire.
      (4.)  They are lines formed when iron filings are sprinkled near a bar magnet.

4.   Magnetic domains help explain which of these observations?
      (1.)  Like charges repel one another.
      (2.)  An iron nail becomes a temporary magnet after being stroked by a permanent magnet.
      (3.)  Magnet force is not influenced by a change in distance from the magnet.
      (4.)  The force of gravity

5.   How is the magnetism of an electromagnet turned on and off?
      (1.) with a galvanometer   (2.)  by adding a more powerful battery
      (3.) by adding more turns in the coil
      (4.) by turning the current on and off
 
6.   As the distance between two magnetic poles decreases, the magnetic force
      (1.) remains constant    (2.) changes unpredictably    (3.) increases
      (4.) decreases

7.   Domains at the north pole of a bar magnet have   (1.)  north magnetic poles only
      (2.) south magnetic poles only   (3.) no magnetic poles
      (4.) both north and south magnetic poles

8.   Which would not change the strength of an electromagnet?
       (1.)  increasing the amount of current   (2.) changing the current's direction
       (3.)  inserting an iron core inside the loop   (4.) increasing the number of loops

9.   Magnetic poles that are alike  (1.) attract each other   (2.) repel each other
       (3.) have no effect on each other   (4.) can attract or repel each other

10.  Breaking a magnet in two results in  (1.) two separate magnets
       (2.) one north pole and one south pole   (3.) two north poles.
       (4.)  two south poles.

11.  The region of magnetic force around a magnet is the   (1.) magnetic domain.
        (2.) magnetic declination.   (3.) magnetic field.   (4.) magnetic pole.

12.  In a magnetized material, all or most of the magnetic domains
       (1.) are randomly arranged.  (2.) are arranged in the same direction.
       (3.) cancel each other out.    (4.) disappear.

13. The angle between geographic north and magnetic north is called
       (1.)  a magnetic domain.   (2.)  a magnetic field.  (3.)  a magnetic pole.
       (4.)  magnetic declination

14. A solenoid (coil of wire with a current source) with a ferromagnetic core is called a(n)
      (1.) superconductor.   (2.) electric circuit.   (3.) electromagnet.
      (4.) permanent magnet

Completion Section

Correctly complete the following statements.

1.   Ferromagnetic materials are highly _____________________.

2.   The individual subunits of a magnet are called ___________________.

3.   Electromagnetic __________________ is the idea that electricity can be produced in a
      coil of wire by moving a magnet within the coil

4.   The magnetosphere is the region of the Earth's ______________ fields

5.   The ________________ is caused by charged particles from the sun penetrating
      the Earth's magnetic fields.

True-False Section

1.   Intense sunspot activity often adversely influences radio and TV communications on Earth.

2.   Compasses are magnetic and will therefore be attracted to the opposite pole,  for this reason,
      the Earth's North Pole is actually the magnetic south pole and this explains why the
      compass needle will always be attracted to the North Pole.

3.   In unmagnetized materials, the domains are aligned in many different directions, canceling each out
 
4.   Temporary magnets may be made from soft iron, they magnetize easily but lose their magnetism quickly.

Short Answer Section

1.     (a.)  Explain why changing the domains within a permanent magnet may cause it to lose its magnetism.
        (b.)  List two things we can do to cause this change in domains to cause a permanent magnet to lose
                its magnetism.
 

2.   List three things that are needed to build an electromagnet.
 

3.   List two ways to increase the strength of an electromagnet.
 

4.  Explain why someone hiking in the woods in Northern NY (they do not have a GPS system, but
     do have a map and a compass) would be interested in the magnetic declination of this area.
 
 
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