Magnetism and Electromagnetism

• What are the two poles of a magnet?

  North and south
• What happens when opposite poles of magnets are brought together?

  They attract each other
• What occurs when like poles of magnets are brought together?

  They repel each other
• Which materials can magnets attract?

  Iron, cobalt, and nickel
• What are non-magnetic substances?

  Materials that are not attracted to magnets
• What is an example of a magnetically hard material?

  Steel
• What is the characteristic of magnetically soft materials?

  They lose their magnetism easily once removed from the magnetic field
• What is the magnetic field?

  The region around a magnet where magnetic forces act
• What do magnetic field lines represent?

  They show the direction and strength of the magnetic force
• In which direction do magnetic field lines travel?

  From the north pole to the south pole of a magnet
• What does the density of magnetic field lines indicate?

  The strength of the magnetic field in that area
• What is induced magnetism?

  When a magnetic material becomes temporarily magnetized in a magnetic field
• What happens to a piece of iron placed near a strong magnet?

  It becomes magnetized with one end as a north pole and the other as a south pole
• What is the application of induced magnetism?

  Creating temporary magnets and electromagnets
• What is the method to investigate the magnetic field pattern for a single bar magnet?

  1. Place a bar magnet on a flat surface.
  2. Cover it with a piece of paper.
  3. Sprinkle iron filings on the paper and tap gently.
  4. Observe the alignment of iron filings along the magnetic field lines.
• What are the field patterns between two bar magnets when opposite poles face each other?

  • Field lines connect directly, indicating attraction.
  • Creates a uniform pattern between the poles.
• What happens to the field lines when like poles of two bar magnets face each other?

  • Field lines curve away from each other.
  • Indicates repulsion between the like poles.
• What characterizes a uniform magnetic field?

  Parallel, equally spaced field lines
• How can a uniform magnetic field be produced using two bar magnets?

  By placing two bar magnets with opposite poles facing each other
• What is an application of uniform magnetic fields?

  Used in devices like mass spectrometers and electron beams
• How does the behavior of magnetically hard materials differ from magnetically soft materials?

  Hard materials retain magnetism, while soft materials lose it easily
• What is the significance of the density of magnetic field lines?

  It indicates the strength of the magnetic field
• What effect does an electric current have when it flows through a wire?

  It produces a magnetic field around the wire.
• How does the direction of the magnetic field relate to the current?

  The direction depends on the direction of the current.
• What does the Right-Hand Grip Rule help determine?

  The direction of the magnetic field lines.
• In the Right-Hand Grip Rule, what does the thumb represent?

  The direction of the current.
• What do the fingers represent in the Right-Hand Grip Rule?

  The direction of the magnetic field lines.
• What are the magnetic field patterns for different configurations of wires?

  • Straight Wire: Circular magnetic field lines.
  • Flat Circular Coil: Concentric circles around each loop.
  • Solenoid: Strong, uniform field inside; resembles a bar magnet outside.
• What is the characteristic of the magnetic field inside a solenoid?

  It is strong and uniform.
• How does the magnetic field outside a solenoid compare to a bar magnet?

  It resembles the field of a bar magnet.
• What does one end of a solenoid act as?

  North pole.
• What increases the strength of the magnetic field in a solenoid?

  Increasing the current through the wire.
• How can the strength of an electromagnet be adjusted?

  By changing the current or number of coils.
• What are the applications of electromagnets?

  • Electric bells
  • Relays
  • Cranes for lifting scrap metal
  • Magnetic locks
• What happens when a current-carrying conductor is placed in an external magnetic field?

  It experiences a force.
• What does Fleming's Left-Hand Rule help determine?

  The direction of force, magnetic field, and current.
• In Fleming's Left-Hand Rule, what does the thumb indicate?

  Direction of Force (Motion).
• What does the first finger in Fleming's Left-Hand Rule represent?

  Direction of Magnetic Field (N to S).
• What does the second finger in Fleming's Left-Hand Rule indicate?

  Direction of Current (Positive to Negative).
• What factors affect the force on a current-carrying conductor in a magnetic field?

  • Strength of the magnetic field (B)
  • Current (I) in the wire
  • Length of wire (L) in the magnetic field