Physics 9 Lesson 62: Wind power – Solar power – Nuclear power
1. Theoretical Summary
1.1. Wind generator
Wind energy is the kinetic energy of air moving through the Earth’s atmosphere.
– The propeller is attached to the rotating shaft of the generator’s rotor. The stator is the electric coil.
- The blowing wind imparts mechanical energy to the propeller ⇨ Rotating propeller pulls the rotor ⇨ The rotor and stator convert mechanical energy into electrical energy.
1.2. Solar battery
Solar cells are flat panels made of silicon. If sunlight shines on that panel, the energy of sunlight will directly convert into electricity.
b) Activities: Wlight → Welectricity
There must be light coming in.
Electricity from wind generators, solar cells is charged to a battery system, when using batteries to generate electricity.
Solar panels are very convenient for high mountains and islands (such as Bach Long Vi island) that do not have the conditions to bring the national electricity grid to the country, especially in tropical countries with many sunny days like in Vietnam. ta.
1.3. Nuclear power plant
– Nuclear power plants convert nuclear energy into electricity. Nuclear power plants can be very powerful but must have very careful protective equipment to prevent radiation that can be deadly.
Reactor: Nuclear W → heat → heat energy of water.
Boiler: Converting nuclear heat → heat of liquid → heat of water.
Generator: Thermal energy of water → mechanical energy of turbine.
1.4. Use energy saving
Electric energy has the characteristic that once it has been produced, it must be used up and cannot be stored (except in the case of small storage in batteries). The large generators that have been turned on must run smoothly, if they can’t need a lot, they will run quickly, when they need less, they should run slowly. Therefore, it is necessary to save, use electricity sparingly during peak hours such as evening and encourage electricity use late at night.
In some machines and tools, the initial energy is converted after a series of processes to obtain the required energy. For example, in a filament light bulb, electrical energy is converted into heat and then heat energy into light energy.
1.5. How to identify generator types?
– Based on the initial form of energy converted into electricity:
Wind power machine: the energy of wind power converts into electricity.
Solar cell: the energy of sunlight converts into electricity.
Nuclear power plant: nuclear energy converts into electricity.
2. Illustrated exercise
Question 1: On sunny days without clouds, the surface has an area of 1m2 of solar panels left in the sun receive a solar energy of 1400J in 1s. What is the minimum area needed to cover the roof of a solar panel to have enough electricity to light two 100W bulbs and a 175W TV. Know that the efficiency of a solar cell is 10%.
Power consumption: 2,100 + 175 = 375W.
The required sunlight power to supply the solar cell: 375.10 = 3750W
Required solar panel area: 3750/1400 = 2.68m2
Verse 2: Sunlight gives every square meter of ground a power of 1.4kW. The efficiency of solar cells is 10%, calculate how much total solar panels are needed to power a school using 20 100W bulbs and 10 75W electric fans.
The total capacity of the school is: P = 20. 100 +10. 75 = 2750W.
Since the efficiency of the solar panel is 10%, the power of sunlight needed to supply the solar cell is: 2750. 10 = 27500W.
The area of solar panels to use is: 27500/1400 = 19.6m2.
3.1. Essay exercises
Question 1: What devices have been used to convert electrical energy into thermal, mechanical, and optical energy used in production?
Verse 2: Show how the wind energy has been converted through the parts of the machine in turn into electricity?
Question 3: Sunlight gives each square meter of ground a power of 2 kW. The efficiency of solar cells is 20%. Calculate how much total solar panels are needed to power a school using 10 95W light bulbs and 9 80W electric fans.
Question 4: How is the current provided by a solar cell different from the current provided by a wind generator?
3.2. Multiple choice exercises
Question 1: Among the power plants, which generator has the most unstable generating capacity?
A. Coal-fired thermal power plant
B. Wind power plant
C. Atomic Power Plant
D. Hydropower plant
Verse 2: The most polluting sources of electricity generation are:
A. wind power plant
B. solar cell
C. hydroelectric plant
D. thermal power plant
Question 3: The energy conversion process in a nuclear power plant is:
A. nuclear energy – mechanical energy – electrical energy.
B. nuclear energy – mechanical energy – thermal energy – electrical energy.
C. nuclear energy – potential energy – electricity.
D. nuclear energy – thermal energy – mechanical energy – electrical energy.
Question 4: Which of the following is not an advantage of wind power?
A. Does not pollute the environment.
B. No fuel consumption.
C. Compact device.
D. Has a very large capacity.
Through this lesson, students will be familiar with the knowledge related to Wind power – Solar power – Nuclear power along with related exercises in many levels from easy to difficult…, they need to understand. :
- Understand the characteristics of wind generators. solar battery.
- Understand the characteristics of nuclear power plants.
- Learn how to save energy.