Page 81 - Big4 Tieng Anh 7 - Tap 2_Neat

These alternative sources include – Solar energy, Wind energy, Geo-thermal energy, Tidal
energy, Biomass energy etc. These energy sources have huge potential of energy and they can
be useful in various ways.

Solar energy is a wide source. Solar cells, solar cookers, solar ponds etc are the devices to
trap solar energy. It can produce electricity, cook food, heat water and can be converted to
other forms of energy.
The solar photovoltaic system which uses solar cells to convert the solar energy into
electrical energy is the most promising and progressive sources of alternative energy.

Wind energy is in form of Kinetic Energy. A blade of windmill is moved by blowing winds
and could be exploited for doing work. Theoretically about 60% of the wind energy can be
converted into other forms of energy. Wind mill farms are being set up in the world to exploit
this energy at suitable places.
Biomass energy is being used in villages but improvement in method and scientific
equipment can increase utilisation. It reduces waste materials and gives cheap energy. Jathropa
is a plant that produces diesel and it is pollution free. Besides the railways lines, Jathropa
planting is in implementation. Hydrogen is also proved to be a great advantageous source of
energy.
Geothermal energy can be used to produce electricity. However, the inner heat of the Earth
not available everywhere which can be commercially exploited. Such potential has been found
in Pegu valley in Jammu and Kashmir in India.
Tidal energy associated with the kinetic energy of tides can be converted into electricity by
using turbine. In the coastal areas this possibility is available.

Answer the questions:

1. What has caused worry about the demand of energy?
................................................................................................................................................

2. What are the alternative sources?
................................................................................................................................................
3. What can solar energy produce?

................................................................................................................................................
4. How many percentages of wind energy cam be converted into other energy?
................................................................................................................................................

5. What is the advantage of biomass energy?
................................................................................................................................................

D. SPEAKING

XI Tell about your habits of watching movies.
You should base on the suggestions below:
-How often to do watch movies?
- When and where do you often watch movies?

-What kinds of movies do you like?
- Who do you often watch movies with?

Big 4 - Bộ đề tự kiểm tra 4 kỹ năng Nghe - Nói - Đọc - Viết tiếng Anh (cơ bản và nâng cao) lớp 7 tập 2|79