Сформулируйте вопросы на английском языке и дайте ответы на них. Что такое длина свободного пробега? Что такое тепловая машина?
What is the mean free path? What is a heat engine?
In physics, the mean free path is the average distance travelled by a moving particle (such as an atom, a molecule, a photon) between successive impacts (collisions),which modify its direction or energy or other particle properties.
The mean free path or average distance between collisions for a gas molecule may be estimated from kinetic theory. Serway's approach is a good visualization - if the molecules have diameter d, then the effective cross-section for collision can be modeled by
using a circle of diameter 2d to represent a molecule's effective collision area while treating the "target" molecules as point masses. In time t, the circle would sweep out the volume shown and the number of collisions can be estimated from the number of gas molecules that were in that volume.
A heat engine typically uses energy provided in the form of heat to do work and then exhausts the heat which cannot be used to do work. Thermodynamics is the study of the relationships between heat and work. The first law and second law of thermodynamics constrain the operation of a heat engine. The first law is the application of conservation of energy to the system, and the second sets limits on the possible efficiency of the machine and determines the direction of energy flow
Heat engines are typically illustrated on a PV diagram
Сформулируйте вопросы на английском языке и дайте ответы на них. Как ведут себя одноименные и разноименные заряды? Сформулируйте свойства заряда.
How do like and unlike charges behave? Specify the properties of the charge.
Like charges repel, unlike charges attract each other.
Properties of electric charge:
1.Two kinds of charges occur in nature, with the property that unlike charges
attract one another and like charges repel one another.
2. Charge is conserved.
3. Charge is quantized.
Сформулируйте вопросы на английском языке и дайте ответы на них. Что такое проводники и полупроводники?
What is the conductors and semiconductors?
It is convenient to classify substances in terms of their ability to conduct electric charge:
Electrical conductors are materials in which electric charges move freely, whereas electrical insulators are materials in which electric charges cannot move freely. Metals are good conductors.
Semiconductors are a third class of materials, and their electrical properties are somewhere between those of insulators and those of conductors. grounded. induction.
Different Types of Conductors
a) Metals are traditional conducting materials. You see them around the house all of the time. It's a metal wire or one of the metal prongs in an electric plug. There are a lot of free electrons in metallic conductors. Free electrons are electrons that are not being held in atoms, and so, can move easily. Some of the best metallic conductors are copper (Cu), silver (Ag), and gold (Au).
b) A semiconductor is a material which has electrical conductivity to a degree between that of a metal (such as copper) and that of an insulator (such as glass). Semiconductors are the foundation of modern electronics, including transistors, solar cells, light-emitting diodes (LEDs), quantum dots and digital and analog integrated circuits.