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

Answer: An electromagnet is a magnet created by passing an electric current through a coil of wire, producing a magnetic field. Unlike a permanent magnet, its magnetism can be turned on or off by controlling the electric current.

Question 2: List three factors that influence the strength of an electromagnet.

Answer: Number of coils in the wire, amount of electric current passing through the wire, and the type of core material used inside the coil.

Question 3: Which core material typically produces a stronger magnetic field in an electromagnet: iron or plastic? Explain why.

Answer: Iron, because it is ferromagnetic and can easily become magnetized, enhancing the magnetic field produced by the coil.

Question 4: Calculate the magnetic field strength (B) of an electromagnet if a current of 3 A passes through a coil with 200 turns and a length of 0.5 meters, assuming a simple solenoid. Use the formula B = (μ₀ * N * I) / L, where μ₀ = 4π x 10⁻⁷ T·m/A.

Answer: B = (4π x 10⁻⁷ T·m/A * 200 * 3 A) / 0.5 m = 1.51 x 10⁻³ Tesla

Question 5: Which safety precaution should be followed when working with high-current electromagnets?

Answer: Ensure the electromagnet is properly insulated and avoid touching the coil while current is flowing to prevent burns or electric shocks.

Question 6: Multiple Choice: Which of the following increases the magnetic field strength of an electromagnet? A) Decreasing the number of coils B) Decreasing the current C) Using a ferromagnetic core D) Using plastic instead of iron

Answer: C) Using a ferromagnetic core

Question 7: Fill in the blank: Increasing the number of coils around the core will __________ the magnetic field strength of the electromagnet.

Answer: increase

Question 8: Explain why electromagnets are preferred over permanent magnets in industrial applications like scrap metal sorting.

Answer: Electromagnets are preferred because their magnetic field can be turned on or off quickly, allowing for precise control in sorting processes. They can also be made very strong by increasing current or turns, and their magnetic strength can be adjusted based on operational needs.

Question 9: Describe a simple experiment to demonstrate how the strength of an electromagnet varies with the number of coils.

Answer: Wrap different numbers of coils around an iron nail, pass the same current through each coil, and test their ability to pick up small metal objects. Observe that more coils result in a stronger magnetic pull.