Unit-11, Lesson-2 (B)
Read the passage. Then answer the questions below.
Countries of the world rely heavily on petroleum, coal and natural gas for their energy sources. There are two major types of energy sources- renewable and non-renewable. Hydro-carbon or fossil fuels are non-renewable sources of energy. Reliance on them poses real big problems. First, fossil fuels such as oil, coal, gas, etc. are finite energy resources and the world eventually will run out of them. Secondly, they will become too expensive in the coming decades and too damaging for the environment. Thirdly, fossil fuels have direct polluting impacts on earth's environment causing global warming. In contrast, renewable energy sources such as wind and solar energy are constantly and naturally replenished and never run out.
Most renewable energy comes either directly or indirectly from the sun. Sunlight or solar energy can be used for heating and lighting homes, for generating electricity and for other commercial and industrial uses.
The sun's heat drives the wind and this wind energy can be captured with wind turbines to produce electricity. Then the wind and the sun's heat cause water to evaporate. When the water vapour turns into rain or snow and flows downhill into rivers or streams, its energy can be captured as hydroelectric energy.
Along with the rain and snow, sunlight causes plants to grow. Plants produce biomass which again can be turned into fuels such as fire wood, alcohol, etc that are called bioenergy.
Scientists have identified Hydrogen as another form of renewable energy source. It is the most abundant element in nature. But it does not exist separately as a gas. It is always combined with other elements, such as with oxygen to make water. Hydrogen, separated from another element, can be burned as a fuel to produce electricity.
Our Earth’s interior contains molten lava which gives off extreme heat. This heat inside the Earth produces steam and hot water which can be used as geothermal energy to produce electricity, for heating homes etc. Ocean energy comes from several sources. Ocean’s force of tide and waves can be used to produce energy. The surface of the ocean gets more heat from the sun than the ocean depths. This temperature difference can be used as an energy source too.
1. Choose the correct answer from the following alternatives.
(a) The main types of energy sources are---.
i. natural and nuclear
ii. renewable and non-renewable
iii. non-renewable, renewable and fossil
iv. natural and man-made
(b) Which of the following has the closest meaning of the word 'extreme'?
i.minimum ii. medium
iii. external iv. immense
আরো পড়ুন : Unit-5, Lesson-4 (C)-এর ৪টি প্রশ্নোত্তর, ১ম পর্ব
(c) We should use renewable energy because it—.
i. never runs out ii. finite
iii. is insufficient iv. can be damaging
(d) What can be trapped as geothermal energy?
I. Steam and river
ii. River and hot water
iii. Steam and hot water
iv. Sunlight and wind
(e) Which of the following gases can be burnt to produce electricity?
i. Carbon di-oxide ii. Hydrogen
iii. Nitrogen iv. Oxygen
(f) The word 'rely' refers to ___ in the passage.
i. depend ii. separate
iii. assist iv. unite
(g) Consumption of fossil fuels—.
i. protects the environment
ii. damages the environment
iii. creates no problem for us
iv. is unlikely to lead us towards a crisis
2. Answer the following questions.
(a) Why will fossil fuels such as oil. coal, gas, etc. run out?
(b) What are the positive aspects of renewable energy?
(c) How does Hydrogen exist in nature?
(d) What is bioenergy? Where do we get it from?
(e) "Reliance on them poses real big problems". How? Explain it in 2/3 sentences.
Answer: 1. (a) ii. renewable and non-renewable, (b) iv. immense, (c) i. never runs out, (d) iii. Steam and hot water, (e) ii. Hydrogen, (f) i. depend, (g) ii. damages the environment.
2. (a) Fossil fuels like oil, coal, gas etc. will run out because they are finite resources. Once they are extracted and burned for energy, they cannot be replaced.
(b) The positive aspects of renewable energy include sustainability, reduced environ-mental impact, energy independence and cost saving. Renewable energy sources are constantly and naturally replenished and never run out.
(c) Hydrogen exists in nature primarily as part of compounds such as in water (H2O) with oxygen and in hydrocarbons.
(d) Plants produce biomass which again can be turned into fuels such as fire wood, alcohol etc. that are called bioenergy. We get bioenergy from organic materials such as plants, crops and organic waste.
(e) Reliance on non-renewable energy sources poses real big problems as these sources are finite and the world will run out of them. They will become extremely expensive in future and too damaging for the environment to repair.
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