Question 1: Define a magnetic field and explain how it is produced around a bar magnet.

Answer: A magnetic field is the region around a magnet where magnetic forces can be detected. It is produced by moving electric charges within the magnet, such as electrons, or by inherent magnetic moments of certain materials like iron.

Question 2: Describe the pattern of magnetic field lines around a bar magnet and explain what the lines indicate about the magnetic field's strength and direction.

Answer: Magnetic field lines around a bar magnet form closed loops exiting from the north pole and entering the south pole. The lines are closest together at the poles, indicating a stronger magnetic field, and their direction shows the magnetic force from north to south outside the magnet.

Question 3: Explain why magnetic field lines never cross each other.

Answer: Magnetic field lines never cross because at any point, the magnetic force has a single direction. Crossing lines would imply two directions at the same point, which is impossible.

Question 4: What is the significance of the Earth's magnetic field for navigation?

Answer: The Earth's magnetic field acts like a giant magnet, with magnetic north and south poles. Compasses align with this field, helping navigators determine direction relative to the Earth's poles.

Question 5: Identify three materials that are attracted to magnets and explain why.

Answer: Materials such as iron, cobalt, and nickel are attracted to magnets because they are ferromagnetic, meaning their magnetic domains can align with an external magnetic field, resulting in attraction.

Question 6: Fill in the blank: Magnetic field lines form _______ loops around a magnet, indicating the magnetic forces are _______ within the field.

Answer: closed, continuous

Question 7: Explain how the magnetic field of a solenoid differs from that of a bar magnet.

Answer: A solenoid produces a magnetic field similar to a bar magnet, with a defined north and south pole, but its magnetic field is concentrated inside the coil, creating a stronger and more uniform field along its axis. Outside, the field lines resemble those of a bar magnet.

Question 8: Describe an experiment to observe the magnetic field around a current-carrying wire.

Answer: Set up a long, straight wire connected to a power supply. Place a compass near the wire and turn on the current. Observe the deflection of the compass needle, which indicates the magnetic field created by the current. The direction of deflection shows the magnetic field's orientation according to right-hand rule.

Question 9: Identify two safety precautions to consider when working with magnetic fields and electric currents in an experiment.

Answer: Ensure that electronic devices are kept away from strong magnetic fields to prevent damage, and avoid handling live electrical wires without proper insulation and safety measures to prevent electric shocks.

Question 10: In a scenario where a magnetic material is placed in a magnetic field, explain the behaviour you would expect and why.

Answer: The magnetic material would become magnetised and attracted towards regions of stronger magnetic field because ferromagnetic materials have magnetic domains that align with the external magnetic field.

Question 11: What is one real-world application of magnetic fields in modern technology?

Answer: Magnetic resonance imaging (MRI) uses strong magnetic fields and radio waves to produce detailed images of the inside of the human body.