Summary of High School Physics Magnetic Field Knowledge Points
Physics in high school is a deeper level than the knowledge learned in junior high school, because physics in high school involves more and more theoretical knowledge and formulas that need to be understood and memorized. So how can you study to improve your physics performance? To study physics, you must understand the characteristics of physics as soon as possible, learn to actively find problems, find problems, and then summarize the solutions. The following are the knowledge points about the magnetic field compiled by MPCO for you, you can use it as a reference.
1. Magnetic phenomenon:
Magnetism: The property that an object can attract substances such as steel, cobalt, and nickel is called magnetism.
Magnet: A magnetic object is called a magnet.
Classification of magnets: ① Shape: bar magnet, hoof magnet, needle magnet;
② Source: natural magnet (magnetite), artificial magnet;
③The length of time to maintain magnetism: hard magnets (permanent magnets), soft magnets.
Magnetic poles: The most magnetic part of a magnet is called a magnetic pole. The magnets are strongest at the ends and weakest in the middle.
Directivity of magnets: A bar magnet or magnetic needle that can rotate freely in the horizontal plane, after stationary, always has one magnetic pole guide (called the south pole, denoted by S), and the other magnetic pole points to the north (called the north pole, denoted by N).
Interaction between magnetic poles: magnetic poles with the same name repel each other, and magnetic poles with different names attract each other.
No matter how many pieces the magnet is broken into, each piece has two magnetic poles.
Magnetization: Some objects will acquire magnetism under the action of a magnet or an electric current. This phenomenon is called magnetization.
Both steel and soft iron can be magnetized: After the soft iron is magnetized, its magnetism is easy to disappear, which is called a soft magnetic material; after the steel is magnetized, its magnetic properties can be maintained for a long time, and it is called a hard magnetic material. So steel is a good material for making permanent magnets.
2. Magnetic field:
Magnetic field: There is an invisible and intangible substance in the space around the magnet, which we call the magnetic field.
The basic nature of the magnetic field: the effect of generating a magnetic force on a magnet placed in it.
The direction of the magnetic field: In physics, the direction of the north pole when the small magnetic needle is at rest is defined as the direction of the magnetic field at that point.
Magnetic field lines: draw some directional curves in the magnetic field, which is convenient for visually describing the magnetic field. Such curves are called magnetic field lines. Understanding of magnetic field lines:
①The magnetic induction line is an imaginary curve, which does not exist in itself;
②The tangent direction of the magnetic induction line is the direction of the magnetic field, which is the direction of the N pole when the small magnetic needle is at rest;
③ Outside the magnet, the lines of magnetic induction start from the N pole of the magnet and return to the S pole. Inside the magnet it’s just the opposite. ④ The density of the magnetic field lines can reflect the strength of the magnetic field. The stronger the magnetism, the denser the magnetic field lines;
3. Geomagnetic field:
Geomagnetic field: The earth itself is a huge magnet, and there is a magnetic field in the space around the earth, which is called the geomagnetic field.
Compass: A small magnetic needle is called the South Pole (S), and the one that points to the North is called the North Pole (N). The small magnetic needle can guide the North because it is affected by the geomagnetic field. The north pole of the geomagnetic field is near the geographic south pole; the south pole of the geomagnetic field is near the geographic north pole. Physics Magnetic Field Knowledge
Geomagnetic declination: the geographical poles and the geomagnetic poles do not coincide, and the north-south direction pointed by the magnetic needle deviates slightly from the geographic north-south direction (magnetic declination). The earliest person in the world to record this phenomenon was a scholar in the Song Dynasty Shen Kuo.
As a high school student, you should be aware of the importance of learning. Learn to take the initiative to learn, especially the three years of high school are the most critical three years, although the study pressure is very high. You should also arrange your study time reasonably. In addition to listening carefully and taking notes in class, you should also do more exercises after class. Exercises are a test of consolidation and review, enriching your own question bank, so that you can face the exam better. Physics Magnetic Field Knowledge