1.
Which term describes the phenomenon where objects are either attracted or repelled to one another due to a force?
Correct Answer
C. Magnetism
Explanation
Magnetism, a fundamental force of nature, governs the attraction or repulsion between objects. It arises from the movement of electric charges. Magnets possess two poles, North and South, and exhibit the principle that opposite poles attract while like poles repel. This force underpins numerous phenomena, from the interaction between magnets to the influence of the Earth's magnetic field on compass needles and magnetic materials. Its study has profound implications across physics, engineering, and technology.
2.
Magnets have a north-seeking pole and a south seeking pole.
Correct Answer
A. True
Explanation
Magnets have a north-seeking pole, often referred to as the North Pole, and a south-seeking pole, commonly known as the South Pole. These poles are so named because a freely suspended magnet aligns itself in the north-south direction, with the North Pole pointing towards the Earth's geographic North Pole and the South Pole pointing towards the Earth's geographic South Pole. This alignment is due to the Earth's magnetic field, which exerts a force on the magnetized material, causing it to align in a north-south direction.
3.
Naturally occurring magnets in nature are called
Correct Answer
D. Loadstones
Explanation
Lodestones are naturally magnetized pieces of the mineral magnetite (Fe3O4) that possess magnetic properties even in their raw state. These magnetic properties were recognized by ancient civilizations, who used lodestones for navigation and various other purposes. When suspended freely, a lodestone aligns itself with the Earth's magnetic field, with one end pointing towards the Earth's geographic North Pole and the other towards the South Pole. This alignment makes lodestones invaluable tools for navigation and understanding the principles of magnetism.
4.
The earth is said to be a small magnet.
Correct Answer
A. True
Explanation
The Earth behaves as a giant magnet due to the movement of molten iron in its outer core. This movement generates a magnetic field, which extends from the Earth's interior into space. The magnetic field has a north and south pole, similar to a bar magnet. Compass needles align with the Earth's magnetic field lines, pointing towards the magnetic north pole. This property allows navigation using compasses, affirming the Earth's status as a magnet.
5.
The preposition that that earth is a magnet was done in the:
Correct Answer
B. 1600's
Explanation
During the 1600s, notable scientists such as William Gilbert conducted experiments and observations that led to the understanding that the Earth behaves like a giant magnet. Gilbert's work, particularly his book "De Magnete" published in 1600, laid the groundwork for the modern understanding of magnetism and the Earth's magnetic field. This marked a significant advancement in scientific understanding and paved the way for further investigations into the nature of magnets and their interactions.
6.
What phenomenon describes the alignment of a freely suspended magnet in the Earth's magnetic field?
Correct Answer
D. Magnetic dip
Explanation
Magnetic dip, also known as magnetic inclination, refers to the angle formed between the direction of the Earth's magnetic field lines and the horizontal plane at a given location. When a freely suspended magnet aligns itself with the Earth's magnetic field, it exhibits magnetic dip, with one end pointing towards the Earth's magnetic North Pole and the other towards the South Pole. This phenomenon is crucial for navigation using compasses and serves as evidence of the Earth's magnetism.
7.
What term describes the property of a material to become magnetized when placed in an external magnetic field and lose its magnetism when the field is removed?
Correct Answer
C. Paramagnetism
Explanation
Paramagnetic materials are those that become magnetized when subjected to an external magnetic field but lose their magnetism when the field is removed. This property arises from the alignment of atomic or molecular magnetic moments in the direction of the applied field. Examples of paramagnetic materials include aluminum, platinum, and oxygen. Understanding paramagnetism is essential for various applications, including magnetic resonance imaging (MRI) in medical diagnostics.
8.
Which law states that the magnetic flux through a closed surface is zero, indicating the absence of magnetic monopoles?
Correct Answer
A. Gauss's Law for Magnetism
Explanation
Gauss's Law for Magnetism. Gauss's Law for Magnetism states that the magnetic flux through any closed surface is zero, implying that magnetic monopoles do not exist. This law, proposed by Carl Friedrich Gauss, is one of the fundamental principles of electromagnetism and plays a crucial role in understanding the behavior of magnetic fields and their interactions with electric charges. It has profound implications in various fields, including theoretical physics and engineering.
9.
What phenomenon describes the increase in the strength of a magnet when placed in an external magnetic field?
Correct Answer
D. Magnetic saturation
Explanation
Magnetic saturation occurs when a material's magnetic domains align to their maximum extent in the direction of an external magnetic field, resulting in an increase in the material's magnetization. Beyond this point, further increases in the external field do not lead to additional magnetization, as the material is already fully magnetized. Understanding magnetic saturation is essential for optimizing the performance of magnetic materials in various applications, such as in magnetic storage devices and electromagnets.
10.
Which phenomenon describes the induction of an electromotive force (EMF) in a closed circuit due to a change in magnetic flux through the circuit?
Correct Answer
C. Faraday's Law of Induction
Explanation
Faraday's Law of Induction states that the electromotive force (EMF) induced in a closed circuit is proportional to the rate of change of magnetic flux through the circuit. This law, discovered by Michael Faraday in the early 19th century, forms the basis of electromagnetic induction, which is fundamental to the operation of electric generators, transformers, and many other electrical devices. Faraday's Law of Induction is a cornerstone of electromagnetism and has wide-ranging applications in power generation and transmission, telecommunications, and electronics.