Question 1: Electromagnets are temporary magnets created by running an electric current through a coil of wire. When electric current flows, it produces a magnetic field, magnetizing the core of the coil. When the current stops, the magnetic field disappears.

Answer: Electromagnets are magnets made by passing an electric current through a coil of wire, which produces a magnetic field. They are temporary and only magnetize when current is flowing.

Question 1: Define an electromagnet and explain how it differs from a permanent magnet.

Answer: An electromagnet is a temporary magnet created by passing electric current through a coil of wire, producing a magnetic field. Unlike a permanent magnet, it only magnetic when current flows.

Question 2: List two factors that can increase the strength of an electromagnet.

Answer: Increasing the number of coils (turns of wire) and increasing the current flowing through the wire.

Question 1: Calculate the magnetic field strength (B) at the center of a solenoid with 500 turns, a length of 0.5 meters, and a current of 2 amperes. Use the formula B = μ₀ * (N/L) * I, where μ₀ = 4π × 10⁻⁷ T·m/A.

Answer: B = 4π × 10⁻⁷ * (500 / 0.5) * 2 = approximately 5.03 × 10⁻⁴ Tesla

Question 1: Describe a simple experiment to demonstrate how increasing the number of coils in an electromagnet affects its magnetic strength. Include safety precautions.

Answer: One experiment involves wrapping different numbers of coils of insulated wire around a iron core, connecting each to a battery, and observing the strength of a nearby small iron object. Increasing the number of coils should increase the magnetic attraction. Safety precautions include ensuring the wire is insulated, avoiding short circuits, and not exceeding the battery's current capacity to prevent overheating.

Question 1: A student measures that increasing the current in an electromagnet from 1 A to 3 A results in the magnetic field strength increasing from 2 × 10⁻⁴ T to 6 × 10⁻⁴ T. Explain the relationship between current and magnetic field in an electromagnet.

Answer: The magnetic field strength is directly proportional to the current flowing through the electromagnet; when the current triples, the magnetic field triples.

Question 1: Describe one way electromagnets are used in everyday technology or industry, explaining why electromagnets are suitable for this application.

Answer: Electromagnets are used in electric relays and circuit breakers to control electrical circuits safely. They are suitable because their magnetic field can be turned on and off quickly and precisely by controlling the electric current.

Question 1: Explain how an electromagnet works, including the role of the coil, current, and core. Discuss two factors that influence its magnetic strength and describe one practical application. (6 marks)

Answer: An electromagnet works by passing an electric current through a coil of wire, creating a magnetic field around the coil. The magnetic field is concentrated and strengthened by the iron core inside the coil. Factors influencing its strength include the number of coils (more coils produce a stronger magnetic field) and the current flowing through the wire (more current increases the magnetic field). A common practical application is in electric cranes used to lift heavy metal objects, where electromagnets can be turned on or off as needed.