Compasses and Electromagnetism

• What does a compass needle point to in a magnetic field?

  The direction of the magnetic field
• What happens to a compass needle when it is not near a magnet?

  It points north to align with Earth's magnetic field
• What is a compass needle described as?

  A small bar magnet
• What rule is used to determine the direction of a magnetic field around a current-carrying wire?

  The right hand thumb rule
• What two factors does the magnetic field strength depend on?

  Size of current and distance from the wire
• How does twisting a wire into a solenoid affect the magnetic field strength?

  It increases the magnetic field strength around the wire
• What happens to the magnetic fields of each turn of wire in a solenoid?

  They add together
• What is the characteristic of the magnetic field inside a solenoid?

  It is strong and uniform
• What shape does the magnetic field around a current-carrying wire resemble?

  The shape of a bar magnet
• What is an electromagnet?

  A solenoid with an iron core
• How does putting an iron core in a solenoid affect its magnetic field strength?

  It increases the magnetic field strength