Answer: A good fuel should have many desirable characteristics. Some of them are as follows:
- It should produce a high amount of energy for each unit of mass or volume.
- It should be easily available and should be easy to transport.
- It should be economical.
What is a good source of energy?
Answer: A good source of energy should be renewable and environment friendly.If you could use any source of energy for heating your food, which one would you use and why?
Answer: I will use LPG (Liquefied Petroleum Gas) for heating my food; because it is easily available in my kitchen, gives no smoke on burning and takes less time to do the job.What are the disadvantages of fossil fuels?
Answer: Following are the disadvantages of fossil fuels:- They are non-renewable
- They produce air pollutants on burning.
Why are we looking at alternate sources of energy?
Answer: Because of growing population, the energy demand is rising. Fossil fuels are going to be exhausted in the near future and burning them is causing air pollution. Hence, we need to find an alternate source of energy which renewable and environment friendly.How has the traditional use of wind and water energy been modified for our convenience?
Answer: Before the beginning of the Industrial revolution, wind and water energy were used for serving many purposes but the ways of their use were not efficient. For example; windmills were used to power smaller mills; like flour mills or saw mills. The flow of water was used for transporting wooden logs. Now-a-days, both wind energy and water energy are being harnessed to produce electricity which means a better and more efficient use of these forms of energy.What kind of mirror; concave or convex or plain would be best suited for use in a solar cooker? Why?
Answer: A concave mirror is best suited for use in a solar cooker. The reason for this is the ability of a concave mirror to converge the solar energy at a point. This enables the concave mirror to produce a larger amount of heat; compared to other types of mirror.What are the limitations of the energy that can be obtained from the oceans?
Answer: Limitations of energy which can be obtained from the oceans:- These forms of energy can be harnessed only in coastal areas; which would leave a vast portion of the human habitation.
- The technologies for harnessing them are still at experimental stage and hence are very costly and less efficient.
What is geothermal energy?
Answer: The energy which can be harnessed from the heat of inside of the earth is called geothermal energy.What are the advantages of nuclear energy?
Answer: Advantages of nuclear energy are as follows:- A small amount of radioactive material can generate a huge amount of energy.
- It does not produce air pollution.
- A nuclear power plant is more efficient than other power plants.
Can any source of energy be pollution free? Why or why not?
Answer: Many sources of energy can be pollution free. When burning of biomass is not involved in production of energy, then there is no chance of pollution. For example; wind energy, hydel energy, solar energy, etc. are pollution free.Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
Answer: Hydrogen is a much cleaner energy source than CNG. CNG (compressed natural gas) is derived from biomass and hence burning the CNG causes air pollution; albeit on a much smaller scale than coal and petroleum. Use of hydrogen as energy source does not polluting gases.Name two energy sources that you would consider to be renewable. Give reasons for your choices.
Answer: Solar energy and wind energy are examples of renewable energy sources because they get quickly replenished.Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choice.
Answer: Coal and petroleum are exhaustible energy sources because their stock is going to be finished in the near future and it takes millions of years for their formation.What are the limitations of extracting energy from: Wind
Answer: Large tract of land is required for establishment of wind farms. They can be established only at those places where wind speed is high enough. Initial cost of establishing a wind farm is very high and the cost of maintenance is also high.Waves
Answer: Energy from waves can be harnessed only at selected places; only in coastal areas.Tides
Answer: Energy from tides can be harnessed only at selected places; only in coastal areas. Technologies for harnessing energy from waves and tides are still at experimental stage and hence are less efficient and very costly.
A solar water heater cannot be used to get hot water on A sunny day A cloudy day A hot day A windy day
Answer: (b) A cloudy day
Which of the following is not an example of a bio-mass energy source? Wood Gobar-gas Nuclear energy Coal
Answer: (c) Nuclear energy
Most of the sources of energy we use represent stored solar energy. Which of the following is not ultimately derived from the Sun’s energy? Geothermal energy Wind energy Nuclear energy Bio-mass
Answer: (c) Nuclear Energy
Compare and contrast fossil fuels and the Sun as direct sources of energy.
Answer: Sun is the direct source of energy, while fossil fuels are formed because of the solar energy stored in them. When green plants prepare food, they convert the solar energy into chemical energy which is stored in the form of biomass. The same biomass gets transferred to the animals. Thus, the energy in the form of biomass which is stored in fossil fuels has come from the sun.Compare and contrast bio-mass and hydroelectricity as sources of energy.
Answer: Biomass and hydroelectricity are different in many aspects. Hydroelectricity is generated using the kinetic energy from moving water, while the energy from biomass is generated by decomposition of farm waste. Since biomass is composed of organic compounds so energy from biomass results in air pollution. Hydroelectricity, on the other hand, is pollution free.
On what basis would you classify energy sources as: - Renewable and non-renewable
- Exhaustible and inexhaustible
Answer: Options given in (a) and (b) are almost same. An energy source which can be quickly renewed is called renewable or inexhaustible. On the other hand, the energy source which cannot be renewed in foreseeable future are called non-renewable or exhaustible.What are the qualities of an ideal source of energy?
Answer: Characteristics of an ideal source of energy:- It should be able to do large amount of work for each unit of mass or volume.
- It should be easily accessible.
- It should be easily transported.
- It should be economical.
What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility
Answer: Advantages of Solar Cooker:- They are environment friendly.
- Use of a solar cooker does not involve recurring expenses on fuel.
Disadvantages of Solar Cooker:- Solar cooker is very slow.
- Solar cooker can work only during summer months and is useless during winters and on cloudy days.
- Solar cooker can be useful at those places which receive plenty of sunshine. This is useless in colder climates.
What are the environmental consequences of increasing demand for energy? What steps would you suggest to reduce energy consumption?
Answer: Environmental consequences of increasing demand for energy are as follows:- Use of fossil fuels is increasing air pollution which is not good for our health.
- Air pollution is causing much damage to the ecosystem.
- Greenhouse effect has resulted in global warming which is manifesting itself in strange changes in the weather pattern around the world.
- Too much exploitation of fossil fuels is going to create a situation when there would be not fossil fuel.
Steps to reduce energy consumption:- Judicious use of energy is the only way.
- Use public transport instead of private modes of transport.
- Use bicycle whenever possible.
- Walk for short distance commute.
- Avoid unnecessary use of modern gadgets which consume lot of energy.
- Get a solar water heater installed for winter.
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