Question 1: Define a magnetic field and describe how it is represented around a magnet.

Answer: A magnetic field is a region around a magnet where magnetic forces can be observed. It is represented by magnetic field lines that emerge from the north pole and enter the south pole of a magnet.

Question 2: Explain how magnetic fields are utilised in the design of electric motors.

Answer: Magnetic fields interact with electric currents in coils within the motor. This interaction produces a force that causes the rotor to turn, converting electrical energy into mechanical energy.

Question 3: What is the purpose of a magnetic shield in engineering applications?

Answer: A magnetic shield is used to protect sensitive electronic equipment from unwanted magnetic fields by redirecting or blocking the magnetic flux.

Question 4: Calculate the magnetic force exerted on a 0.5 A current-carrying wire placed in a magnetic field of 0.2 T, when the length of the wire in the field is 2 metres and the angle between the wire and the magnetic field is 90°.

Answer: F = BIL sin θ = 0.2 T × 2 m × 0.5 A × sin 90° = 0.2 × 2 × 0.5 × 1 = 0.2 N

Question 5: Identify three variables that affect the strength of a magnetic field generated by a solenoid.

Answer: Number of turns in the coil, the current passing through the coil, and the length of the solenoid.

Question 6: Describe a simple experiment that could demonstrate the magnetic field around a current-carrying wire.

Answer: Connect a long insulated wire to a power supply, place small paperclips or iron filings around the wire, and turn on the current. Observe how the iron filings align along the magnetic field lines created by the current.

Question 7: A data collection shows that when the current in a coil increases, the magnetic field strength also increases. Explain this relationship.

Answer: The magnetic field strength is directly proportional to the current in the coil; increasing current produces a stronger magnetic field.

Question 8: In the context of electric vehicles, how are magnetic fields used in regenerative braking systems?

Answer: Magnetic fields interact with the motion of the motor's components to generate electricity during braking, converting kinetic energy into electrical energy to recharge the batteries.

Question 9: Explain the safety precautions engineers must consider when working with strong magnetic fields in industrial settings.

Answer: Engineers must ensure that magnetic fields do not interfere with electronic devices or data storage, implement safety zones to prevent accidental exposure to strong fields, and use non-magnetic tools to avoid projectiles. Proper shielding and warning signs should also be employed.

Question 10: A new magnetic levitation train uses powerful electromagnets to lift and propel the train. Describe how magnetic fields enable this technology.

Answer: Electromagnets generate magnetic fields that repel the track's magnetic surface, levitating the train, while controlled magnetic forces are used to propel it forward, reducing friction and enabling high speeds.