Question 1: A solenoid is a long coil of wire wrapped in many turns that produces a magnetic field when an electric current passes through it. The magnetic field inside a solenoid is similar to that of a bar magnet, with a distinct north and south pole.

Answer: A coil of wire that creates a magnetic field when current flows through it, resembling a bar magnet.

Question 1: Explain why the magnetic field inside a solenoid is uniform and strong compared to the field outside.

Answer: Because the turns of wire are closely packed, creating a uniform magnetic field inside, while the field outside is weaker and less uniform.

Question 2: Describe how increasing the number of turns in a solenoid affects its magnetic field strength, assuming current remains constant.

Answer: Increasing the number of turns strengthens the magnetic field because the field is proportional to the number of turns.

Question 1: Calculate the magnetic field strength inside a solenoid of length 0.5 m, with 200 turns, carrying a current of 3 A. Use the formula B = μ₀ * (N/L) * I, where μ₀ = 4π × 10⁻⁷ T·m/A.

Answer: B = 4π × 10⁻⁷ * (200/0.5) * 3 ≈ 1.51 × 10⁻³ T

Question 2: A solenoid has 500 turns and is 1 metre long. If the magnetic field inside is measured as 2 × 10⁻³ T when a current flows, what is the current flowing through the solenoid?

Answer: I = B * L / (μ₀ * N) = 2 × 10⁻³ * 1 / (4π × 10⁻⁷ * 500) ≈ 3.18 A

Question 1: Describe a simple experiment to demonstrate the magnetic field inside a solenoid without using any visual aids. Include the variables you would control and safety precautions.

Answer: Use a compass placed at different points inside and outside the solenoid to observe the magnetic field. Control variables such as current and number of turns. Safety precautions include ensuring the current is not too high to prevent overheating and handling wires carefully to avoid short circuits.

Question 1: A solenoid with 300 turns and length 0.75 m carries a current of 2 A. The measured magnetic field is 1.2 × 10⁻³ T. Analysing this data, discuss whether the magnetic field strength is proportional to the current, assuming other factors are constant.

Answer: Yes, the magnetic field is proportional to current as increasing current would increase the magnetic field, consistent with the formula B = μ₀ * (N/L) * I.

Question 1: Describe one practical application of solenoids in industry or technology, explaining how their magnetic properties are utilised.

Answer: Solenoids are used in electric door locks, where passing current through the coil creates a magnetic field that activates a locking mechanism.

Question 1: Analyse how changing the material of the core inside a solenoid from air to iron would affect its magnetic field and practical use.

Answer: Replacing the core with iron increases the magnetic field significantly because iron is ferromagnetic, which enhances the magnetic flux. This makes solenoids more effective in devices like electromagnets and transformers, where a stronger magnetic field is beneficial.