Permanent & Induced Magnetism, Magnetic Forces & Fields

• What are the ends of a magnet called?

  Poles
• How many poles do magnets have?

  Two poles: a north and a south
• What happens when two magnets are held close together?

  There will be an attractive or repulsive force between them
• What does the Law of Magnetism state?

  Two like poles repel each other, and two unlike poles attract each other

  
• What type of force is the attraction or repulsion between two magnetic poles?

  It is an example of a non-contact force
• What are magnetic materials?

  Materials that are attracted to a magnet
• Which metals are considered magnetic?

  Iron, Cobalt, Nickel

  
• Why is steel considered a magnetic material?

  Because it is an alloy that contains iron
• How can you test if a material is a magnet?

  Bring it close to a known magnet; if it can be repelled, it is a magnet
• What happens to a magnetic material when it is placed in a magnetic field?

  It can temporarily become a magnet

  
• What is induced magnetism?

  When a magnetic material is placed in a magnetic field and becomes a magnet temporarily

  
• What happens to a magnetic material when it is removed from a magnetic field?

  It will lose most or all of its magnetism quickly
• What is the definition of a magnetic field?

  The region around a magnet where a force acts on another magnet or magnetic material
• How are magnetic field lines used?

  To represent the strength and direction of a magnetic field
• What does the spacing of magnetic field lines indicate?

  The strength of the magnetic field
• What do closely spaced magnetic field lines indicate?

  A strong magnetic field
• What do widely spaced magnetic field lines indicate?

  A weak magnetic field
• In what direction do magnetic field lines always go?

  From north to south

  
• What is the strongest part of a magnetic field?

  At the poles of the magnet
• How does the magnetic field change with distance from the magnet?

  The magnetic field becomes weaker as the distance increases
• What happens to magnetic field lines when two bar magnets are attracting each other?

  The field lines will look different than when they are repelling

  
• What is a uniform magnetic field?

  A field that has the same strength and direction at all points
• How can you show that a magnetic field is uniform?

  By having equal spacing between all magnetic field lines
• What is the direction of a magnetic field line at any point?

  From the north pole of a magnet to the south pole

  
• How can the shape and direction of a magnetic field be investigated?

  Using plotting compasses
• What does the arrow of a plotting compass represent?

  The north pole of the compass
• What is the first step in investigating the shape and direction of a magnetic field?

  Place the magnet on top of a piece of paper and draw a dot at one end
• What should you do after placing the plotting compass next to the dot?

  Draw a new dot at the other side of the compass needle
• What should you do after creating a chain of dots?

  Link the dots using a smooth curve to represent the magnetic field line
• What does the Earth's magnetic field do in the absence of any magnet?

  A magnetic compass will always point north
• Why does the north arrow on a magnetic compass point towards the geographic North Pole?

  Because the geographic North Pole is a magnetic south pole

  
• What is the relationship between the Earth's magnetic poles and the compass?

  The north pole of the magnetic compass is attracted to the Earth's magnetic south pole

  
• What is the nature of the geographic South Pole in relation to magnetism?

  It is a magnetic north pole

  
• Why is the Earth's north pole considered to act like the south pole of a magnet?

  Because the north pole of a magnet is attracted to it