Given the following options, which statement best describes what happens when an electron is released from rest near the north pole of a bar magnet? 0 The electron feels force due to the magnet. 0 The electron is attracted to the north pole. 0 The electron moves towards the south pole. 0 The electron is repelled from the north pole. Question 28 Ferromagnets, or “permanent magnets,” are the most common way we encounter magnetism in everyday circumstances. Choose the statements below that correctly describe how ferromagnets work: Ferromagnets are made of materials which form magnetic domains, macroscopic regions where the magnetic poles of individual atoms are aligned. Ferromagnets are pieces of Earth’s magnetic core that have broken off and drifted over the upper crust over millions of years. There is a source of energy needed to power the magnetic fields generated by ferromagnets. Ferromagnets contain an imbalance of magnetic poles (more north poles than south poles, or vice versa), which produces magnetic fields.
The Correct Answer and Explanation is:
Correct answers:
- What happens when an electron is released from rest near the north pole of a bar magnet?
Correct answer: The electron feels force due to the magnet. - Which statements correctly describe how ferromagnets work?
Correct answer: Ferromagnets are made of materials which form magnetic domains, macroscopic regions where the magnetic poles of individual atoms are aligned.
Explanation
When an electron is released from rest near the north pole of a bar magnet, it experiences a magnetic force due to the magnetic field generated by the magnet. However, it is important to understand that magnetic fields do not directly cause stationary charged particles to move. The magnetic force on a charged particle depends on its velocity and is described by the Lorentz force law: F = q(v × B). Since the electron starts from rest, there is no initial velocity, and thus, the magnetic field does not exert a force on it immediately. However, due to quantum effects or if any slight motion arises, the electron may begin to experience a force. Therefore, the most accurate answer is that the electron feels force due to the magnet, acknowledging that magnetic fields influence moving charges.
As for ferromagnets, they are composed of certain materials like iron, cobalt, and nickel. These materials have regions called magnetic domains. Within each domain, many atomic magnetic moments are aligned in the same direction, giving rise to a net magnetic field. When most or all of the domains are aligned throughout the material, it behaves as a magnet. This alignment happens naturally in ferromagnetic materials and does not require an external power source. So, the magnetic field generated by a ferromagnet does not need a continuous energy input to be maintained.
The other choices are incorrect. Ferromagnets are not fragments of Earth’s core. Also, magnetic poles always exist in north-south pairs; there is no such thing as an isolated magnetic monopole, so it is not possible to have an imbalance of magnetic poles. Therefore, the correct understanding lies in the internal structure and domain alignment of the ferromagnetic material.
