Shanghai New Textbook Physical Historical Facts of College Entrance Examination

1. Maxwell's electromagnetic theory

Firstly, the classical electromagnetic theory is established to explain the existence of electromagnetic waves.

(1) A changing electric field will generate a magnetic field, and a changing magnetic field will generate an electric field.

(2) The changes of electric field and magnetic field are always produced alternately, thus forming an inseparable unity.

(3) Electromagnetic waves are formed from the occurrence area to the surroundings.

Hertz obtains electromagnetic waves by experimental methods.

2. Electromagnetic spectrum (wavelength from small to large, frequency from high to low)

name

Gamma ray

roentgen rays

ultraviolet ray

visible light

(Red, orange, yellow, green, indigo)

infrared ray

radio wave

(micro, ultra-short, short, medium and long)

Features (corresponding here)

Strong penetrating power

High frequency,

Strong penetrating power

fluorescence effect

chemical action

Visual effect

Strong thermal effect

Violent fluctuation

App application

Knife,

Industrial flaw detection

physical examination

Fluorescent lamp,

Sterilization,

Prevent forgery

Take pictures of ...

Infrared heating,

Thermal imaging rocker

Microwave heating,

Radio wave communication technology

Two. Microstructure of matter

A. Nuclear structure model of atom

1. Discovery of electrons

Tom Musun's cathode ray experiment found electrons.

2. The nuclear structure model of atoms

Rutherford's α-particle scattering experiment denied Thomas Musun's nuclear-free atomic structure model and proposed a nuclear structure model.

3. Rutherford's nuclear structure model

(1) Internal:

There is a small nucleus called nucleus at the center of the atom.

(2) All positive charges and almost all atomic masses are concentrated in the nucleus.

(3) Electrons with negative charges keep moving around the nucleus outside the nucleus (the centripetal force required for electrons to move around the nucleus is the electric field force exerted on it by the nucleus).

B. Radioactivity of substances and its applications

1. Natural radioactivity phenomenon

The radiation emitted by the nucleus is called natural radioactivity (Bekkerel).

2. Three kinds of rays

Essence (corresponding here)

penetrability

Ionization ability

Alpha ray

High-speed alpha particle (helium nucleus) flow

weakest

the strongest

β ray

High-speed electron flow

faintish

strong

Gamma ray

High frequency electromagnetic wave

High frequency and high energy γ photon flow

the strongest

weakest

3. Tools

(1) Yunwu

(2) Geiger Miller counter

(3) Other detectors (semiconductor detector, multi-wire proportional chamber, bubble chamber, scintillation detector).

4. Application of radioactivity

(1) Radiation emitted by radioactive elements

(2) Radioisotopes as tracer atoms

5. Radioactive radiation protection

(1) Excessive radiation is harmful to human body, and the radiation dose equivalent acceptable to the general public in one year is about 5000 μ Sv.

(2) the shielding effect of metal on radiation

C. Composition of atomic nuclei

1. Discovery of the atom

Rutherford bombarded nitrogen nuclei with alpha particles and found protons, that is, hydrogen nuclei, and found the existence of protons and neutrons. This was the first artificial transformation.

2. The discovery of neutrons

Chadwick bombarded beryllium with alpha particles and found uncharged neutrons.

3. The composition of the nucleus

The nucleus of (1) is composed of protons and neutrons, which are collectively called nucleons.

(2) A: mass number, nucleon number

Z: number of protons, number of nuclear charges, atomic number, number of extranuclear electrons.

Neutron number: A-Z

(3) Isotope

Atoms with different numbers of neutrons but the same number of protons in the nucleus are called isotopes.

(4) Nuclear power

Gravitation between nucleons

Features: powerful function and short range.

D. heavy nuclear fission

1. nuclear energy

Energy released when the nuclear structure changes.

Step 2 split

When a heavy nucleus is bombarded by other particles (such as neutrons), the process of splitting into two or more intermediate-mass nuclei is called fission.

Neutrons and a lot of energy will be released during fission.

3. Chain reaction

Neutrons released in heavy nuclear fission cause fission of other heavy nuclei, which can make fission continue. This is the chain reaction.

The chain reaction makes it possible to use nuclear energy on a large scale.

4. Chain reaction conditions

(1) In order to make the chain reaction of fission easy to occur, it is best to use pure uranium 235.

(2) The minimum volume of uranium block that can produce chain reaction is called its critical volume.

E. reactors and nuclear power plants

1. reactor

A device that artificially controls the speed of nuclear fission chain reaction and obtains nuclear energy is called a reactor.

Composition: nuclear fuel rod, moderator, control rod, cooling system and protective layer.

2. Nuclear power plants

A power plant that converts nuclear energy released by nuclear fuel fission in a reactor into electric energy is called a nuclear power plant.

Composition: nuclear island, conventional island and supporting facilities.

Difference from general power plants: nuclear island part

3. Nuclear power is an economical, safe and clean energy source.

Three. universe

A. Law of universal gravitation

1. Gravity

There is gravity between any objects with mass, and this gravity is called gravity.

2. The law of universal gravitation

The gravity between two objects is directly proportional to the product of their masses and inversely proportional to the square of their distance, and the direction is on the connecting line of the two objects. This is the law of universal gravitation.

3. Cavendish torsion scale experiment

The key part of the experiment: plane mirror

Function: Solve the problem of measuring gravity constant.

4. Gravity and gravity

Gravity produces gravity; G decreases with the increase of height and increases with the increase of latitude, but in the usual calculation, the gravity near the earth's surface is about equal to the gravity of the earth.

B. the basic structure of the universe

The earth and the moon

The earth revolves around the sun at a high speed.

The moon always faces the earth on the same side. Tidal phenomena are mainly caused by the different gravitational forces exerted by the moon on different parts of the earth.

The average density of the moon is almost equal to the average density of the crust.

2. The Sun and Planets

The sun is a gas planet, which can emit light and heat by itself.

Mercury, Venus, Earth and Mars are called inner planets. They are also called "Earth-like planets". Their shells are made of hard rocks, and their cores are metals such as iron.

Planets revolve around the sun in almost the same plane under the gravity of the sun. The closer a planet is to the sun, the faster its revolution speed. (related to gravity, close distance, high gravity and fast speed)

3. Milky Way and Extragalactic Galaxies

A galaxy is a material system in the universe, which consists of a large group of moving stars, a lot of gas and dust.

Star systems outside the Milky Way are called extragalactic galaxies.

Galaxies can be roughly divided into spiral galaxies, elliptical galaxies and irregular galaxies.

The Milky Way is a spiral galaxy with the sun on one of its spiral arms.

We can use the nature of the earth's motion around the sun to measure the distance between stars. This distance measurement method is called annual parallax method.

Besides the sun, the nearest star is around 4.31.y.

4. the universe

Astronomers define all space and everything in it as the universe.

Several clusters of galaxies form a larger supercluster.

C. evolution of celestial bodies

1. Classification of stars

According to the physical characteristics of stars, the main characteristics used for classification are the volume, temperature and brightness of stars.

The observed stars include Supergiant star, giant stars, main sequence stars, white dwarfs and neutron stars.

White dwarfs are as big as the earth, and neutron stars are only a few kilometers to dozens of kilometers in diameter.

The color of a star shows its temperature, and the star with lower temperature appears dark red in the sky. A hotter star (surface temperature higher than10000 C) will look slightly bluer than the sun.

In Herodotus diagram, most stars form a diagonal of the main sequence, which is called in astronomy. On this diagonal line of the main sequence, the brightness of the star is getting bigger and bigger, indicating that the temperature on the surface of the star is higher.

2. Several stages of stellar evolution

Star evolution can be divided into birth period, existence period and death period.

The Supergiant star, giant stars, main sequence stars, white dwarfs and neutron stars we have observed are all star forms of different ages.

The life of a star depends on its mass. Quality is great, but life is short. The sun is in its heyday.

When a star becomes a red giant or Supergiant star, it means that the star will spend its glorious life.

Summary: Participating physicists and their contributions to physics.

Faraday discovered the phenomenon of electromagnetic induction.

Inmaxwell first established the classical electromagnetic theory and predicted the existence of electromagnetic waves.

Dehz obtained electromagnetic waves through experiments for the first time.

Tom Musun discovered the electron. The discovery of electrons confirmed that atoms can be separated. Electrons are components of atoms.

Rutherford denied Tom Musun's nuclear-free atomic structure model through the scattering experiment of α particles, and put forward the nuclear structure model of atoms.

Faber's discovery of natural radioactivity shows that the nucleus has a complex structure.

Rutherford bombarded the nitrogen nucleus with alpha particles, and through artificial transformation, protons appeared in the nucleus for the first time.

Chadwick discovered uncharged neutrons through experiments and analysis.

De Kepler discovered and published three laws of celestial motion by using a large number of astronomical observation data left by Danish astronomer Tycho.

Newton discovered gravity, and on the basis of predecessors, summed up the law of gravity.

England and cavendish verified the law of universal gravitation through torsion balance experiments, and measured the gravitational constant.