Which is the best material to use superconductor for an electric motor or an electric heater?

Of course, the motor is chosen, because there is resistance to generate heat energy, and the motor is to convert electrical energy into kinetic energy, if the heat is generated, the energy will be lost, superconductor is an ideal material without resistance, that is, it will not generate heat for a long time. Therefore, the motor chooses a superconductor. If you choose a superconductor for an electric heater, it will never heat up.

Electric heater uses the thermal effect of electric current to work, and the magnitude of the thermal effect can be judged by Joule's law, while the resistance of superconductors is 0, and it can be known that no heat will be produced according to Joule's law; An electric motor is a device that converts electrical energy into mechanical energy, so it requires as little heat as possible, so superconductors are used.

The main function of the wire is to transport electrical energy, so it is also necessary to produce as little heat as possible, according to Joule's law, the smaller the resistance, the better.

The smaller the conductor resistance, the less electrical energy is consumed in the process of transmitting the current (consumed equals wasted). The electric motor is an electrical appliance that converts electrical energy into mechanical energy, and the less electrical energy is consumed, the more mechanical energy is generated by the conversion. The working principle of an electric water heater is that a high-resistance material is obstructed by the flow of electric currents to generate heat energy.

If a superconductor with no resistance is used to make a water heater, it will never be able to boil the water. If it is used to make electric motors, it can reduce power loss and improve efficiency!

The heating power should be calculated in terms of IR squared, and the superconductor has no resistance, so it does not generate heat. Using it as an electric heater will not have temperature at all, what is it called an electric heater; And the electric motor just needs to avoid heating. Heat generation can reduce work efficiency (except for pure resistors for the purpose of generating heat, such as:

Electric kettles, electric heaters, etc. The pure resistor efficiency is considered to be 100%), so superconductors are applied to electric motors.

According to Q=I2RT, you know that the resistance of the electric heater is greater than that of the electric motor, so what your teacher said is still correct.

If the resistance of the electric heater is too small, it will easily burn out, which is equivalent to a short circuit. The smaller the wire resistance, the less consumption.

It doesn't seem to be good... Superconducting materials require extremely low temperatures, so how can they be done with motors and electric heaters?

(1) From the inscription, heating and pulping are carried out alternately, and the motor and the electric heater can work independently and do not affect each other, so they are connected in parallel;

2) The amount of heat absorbed by water is:

Q suck. =cm（t2 -t1

j∕（kg?℃）

j；(3) The motor works for 6 minutes and consumes

w=pt=1000×10-3kw×6

h=?h So the answer is: and;

The resistance of the superconductor is zero, so the superconductor cannot be used as the heating element of the electric heater, otherwise the electric heater will not work

Due to the resistance of the transmission line, it is inevitable that there will be a loss of electrical energy in the transmission process If the transmission line is made of superconductors, there will be no energy loss in the circuit

So the answer is: no; Not consumed

Which one you like the most, the one you are best at, that's good!

"Polymer Materials and Engineering": It is a discipline that cultivates senior engineering and technical talents who have knowledge of polymer materials and engineering, and can be engaged in scientific research, technology development, process and equipment design, production and operation management in the fields of synthesis, modification and processing of polymer materials. But the most important thing is research, of course, there is no problem in learning well, and the song is also the current development trend.

But the average may not be so good.

Materials science and engineering involves a wide range of majors, so when employed, it feels like "all-in-one", and the characteristic direction of materials physics is in the fields of semiconductor physics, electronic materials, and microelectronic devices, such as CPU. It has high requirements for students' mathematics and physics foundation, and focuses on cultivating students' application ability and innovation ability in the development of new electronic materials and microelectronic device processes, analysis and design. The employment prospects of materials physics majors are very broad.

The demand for modern materials or new materials to serve high-tech, modern industry and national defense is increasing, and the research and development speed of new materials is getting faster and faster, so the new concepts, new theories, new technologies, new methods, new processes, new products and new problems that emerge are increasingly needing the joint efforts of materials scientists and physicists to summarize, sort, summarize and innovate. The resulting major of materials physics is undoubtedly the result of the intersection and penetration of multidisciplinary knowledge. It brings new space to the research, development and application of modern materials and the development of related sciences.

It provides perfect and systematic theoretical guidance and technical support for the sustainable development of new materials. Therefore, the employment prospects of materials physics majors are very broad.

Graduates are suitable for applied research, scientific and technological development, production technology and management in materials-related enterprises, undertakings, technical and administrative departments, and are suitable for scientific research and teaching in scientific research institutions and colleges and universities, and can continue to study for master's degrees in materials-related engineering disciplines and interdisciplinary disciplines.

A. The core component of LED lamps is made of semiconductor materials, so A is in line with the topic;

b The electric heater uses an electric current to generate heat through a resistance wire, and cannot be made of superconductor materials to make heating equipment, so b does not conform to the topic;

c The launch vehicle uses liquid hydrogen as the fuel of the rocket, because the liquid hydrogen has a large calorific value, so c is in line with the topic;

d Because the specific heat capacity of water is larger, compared with other substances, the same quality of water rises to the same temperature, and the water absorbs more heat, so it cools the car engine with water, so d is in line with the topic;

Therefore, ACD is chosen

(1) In the two wires "A" and "B" in the figure, "A" is connected to the switch and the right hole of the socket, so it is a live wire;

The soymilk machine belongs to the electrical appliances with a metal shell, therefore, a three-prong socket must be used, so the socket "D" should be selected;

2) Heat absorbed by soybean milk: Q suction = cm (t-t0) = ?℃）2kg×（100℃-20℃）=；

3) Because heating and pulping are carried out alternately, the power of heating is larger, which is 880W, which is obtained by P=UI, and the maximum current at this time: I=P

u=880w

220v4a；

4) From p=ur, the resistance of the heating wire when the soymilk machine is heated: r=u

p=(220v)

880W55, when the voltage is only 200V, its actual power P real = U2 real.

r=(200v)

So the answer is: (1)a; d；