Chicken curry masala

• What is the topic of the study material?

  Magnetism and Magnetic Fields
• What do magnets have that allows them to affect other magnets and magnetic materials?

  Magnets have magnetic fields
• How can one visualize magnetic field patterns?

  By using diagrams to draw field lines around and between magnets
• What is the effect of magnets on magnetic materials and other magnets?

  Magnets affect magnetic materials and other magnets
• How do you plot the magnetic field lines of a bar magnet using a compass?

  1. Place the compass near one pole of the bar magnet.
  2. Mark the direction of the compass needle.
  3. Move the compass to the next position and repeat.
  4. Connect the points to visualize the field lines.
• Why is a piece of copper not attracted to or repelled by a magnet?

  Copper is not a magnetic material
• What is the relationship between a current-carrying wire and its magnetic effect?

  A current-carrying wire has a magnetic effect
• How does the magnetic field around a straight wire behave?

  The magnetic field forms concentric circles around the wire
• What happens to the magnetic field around a flat circular coil?

  The magnetic field is concentrated in the center and resembles that of a bar magnet
• How does the strength of the magnetic field change with distance from the current-carrying wire or solenoid?

  The magnetic field gets stronger as you get closer
• What is the magnetic field around a solenoid like?

  The magnetic field inside a solenoid is strong and uniform
• What happens when a current-carrying conductor is placed in a magnetic field?

  It experiences a force due to the interaction of the magnetic fields
• At what angle must a wire be positioned to experience maximum force in a magnetic field?

  The wire must be at 90° to the magnetic field
• What factors can increase the force experienced by a current-carrying conductor in a magnetic field?

  The force increases with a stronger magnetic field, increased current, or longer wire length
• How can the direction of the force on a wire be changed?

  By applying a current in a different direction
• What is the equation used to calculate the force on a current-carrying conductor?

  Force (N) = magnetic flux density (T) × current (A) × length (m) or $F =$$B \times I \times l$
• If a current-carrying wire is placed at 90° to a magnetic field, what is the force acting on it?

  The force is maximized
• What happens in a simple experiment with a magnet and a compass?

  1. A magnet is placed over a compass.
  2. The compass needle, being a small magnet, experiences a force.
  3. The needle rotates due to opposite forces on each pole.
  4. The direction of the force can be reversed by changing the current flow.
• How does a simple electric motor utilize magnets and a current-carrying coil?

  A current-carrying coil between two magnets experiences forces that cause it to rotate
• What role does the split-ring commutator play in a d.c. motor?

  It keeps the motor rotating in the same direction by maintaining contact every half turn
• How can the direction of a motor be reversed?

  By swapping the polarity of the d.c. supply or reversing the magnetic poles
• How does a loudspeaker work using magnets and a coil of wire?

  1. A coil of wire is surrounded by a strong magnet.
  2. Alternating current is fed to the coil.
  3. The interaction between the magnetic field and current forces the coil to move.
  4. The coil's movement vibrates a cone, creating sound.
• What is electromagnetic induction?

  It is the process that generates electricity through a changing magnetic field
• How do alternators generate alternating current?

  By rotating a magnet in a coil of wire, inducing an alternating p.d.
• What is the function of slip rings in an alternator?

  They maintain contact with brushes to produce alternating current without interruption
• How do dynamos generate direct current?

  By rotating a coil in a magnetic field and using a split-ring commutator
• How do microphones work due to electromagnetic induction?

  1. A diaphragm replaces the cone in a loudspeaker.
  2. Sound waves cause the diaphragm to move.
  3. The movement induces a p.d. across a coil of wire.
  4. This induces variations in current in the electrical circuit.
• What is the role of transformers in electrical systems?

  Transformers change the potential difference of an alternating current
• What happens when an alternating p.d. is applied across the primary coil of a transformer?

  It produces an alternating magnetic field
• How does the number of turns in a coil affect the induced potential difference in a transformer?

  The ratio of potential differences is the same as the ratio of the number of turns
• What is the output voltage of a step-down transformer with a primary coil of 3900 turns and a secondary coil of 2400 turns if the input voltage is 6.5 V?

  The output voltage is $4.0 V$
• What are the two types of transformers and their functions?

  • Step-down transformers: reduce voltage (fewer turns in secondary coil)
  • Step-up transformers: increase voltage (more turns in secondary coil)