What are the environmental consequences of the increasing demand for energy ?
[question] Question. What are the environmental consequences of the increasing demand for energy ? What steps would you suggest to reduce energy consumption ? [/question] [solution] solution: (i) Burning of fossil fuels to meet increasing demand for energy causes air-pollution. (ii) Construction of dams on rivers to generate hydro-electricity destroys large ecosystems which get submerged under water in the dams. Large amounts of methane (which is a greenhouse gas) is produced when submerged vege...
What are the advantages and disadvantages of using a solar cooker ?
[question] Question. What are the advantages and disadvantages of using a solar cooker ? Are there places where solar cookers would have limited utility ? [/question] [solution] solution: Advantages of solar cooker (1) Using solar cooker saves our conventional fuels. (2) Solar cookers do not cause any environmental pollution. (3) The nutrients in the food are not destred if the food is prepared in solar cooker as the temperature inside it is not so high. (4) Four food items can be cooked at a ti...
What are the qualities of an ideal source of energy?
[question] Question. What are the qualities of an ideal source of energy? [/question] [solution] solution: (1) It should have a high calorific value [calorific value is defined as the number of heat units produced when unit mass of fuel is burnt] Thus, a good fuel should liberate more heat per unit mass. (2) It should have low moisture content. (3) It should have low non-combustible matter like ash, etc. That is, it should leave low ash and other residual matter after combustion. (4) Its product...
On what basis would you classify
[question] Question. On what basis would you classify energy sources as (a) renewable and non-renewable ? (b) exhaustible and inexhaustible ? Are the options given in (a) and (b) the same ? [solution] solution: (a) Renewable sources of energy are those which (i) can be replaced as we use them and (ii) can be used to produce energy again and again. Non-renewable sources of energy are those which cannot be replaced once these are used. (b) Exhaustible sources of energy are those whose supply is li...
What are the limitations of extracting energy from
[question] Question. What are the limitations of extracting energy from (a) the wind (b) waves (c) tides ? [/question] [solution] solution: (a) Limitations of Wind Energy (1) The wind is very unpredictable, destructive source of energy. (2) It is not steady and consistent at all places. Thus, it can be used at the places where it is available, with consistent and steady characteristics. Wind energy farms can be established only at those places where wind blows for the greater part of a year. (3)...
Compare and contrast fossil fuels and
[question] Question. Compare and contrast fossil fuels and the Sun as sources of energy [/question] [solution] solution: (1) The reserves of fossil fuels are limited i.e., exhaustible and they have high cost. But, solar energy is available in abundance i.e., it is inexhaustible and that too, without any cost. (2) Fossils fuels cause air pollution on burning whereas solar energy is pollution-free. (3) Fossil fuels can provide energy at any required time whereas solar energy is not available every...
Most of the sources of energy we use represent stored solar energy.
[question] Question. 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 ? (a) geothermal energy (b) wind energy (c) fossil fuels (d) bio-mass [/question] [solution] solution: Option (a) geothermal energy is correct. [/solution]...
Which of the following is not an example
[question] Question. Which of the following is not an example of bio-mass energy source ? (a) wood (b) gobar gas (c) atomic energy (d) coal [/question] [solution] solution: Option (c) atomic energy is correct. [/solution]...
A solar water heater cannot be used to get hot water on
[question] Question. A solar water heater cannot be used to get hot water on (a) a sunny day (b) a cloudy day (c) a hot day (d) a windy day [/question] [solution] solution: Option (b) a cloudy day is correct. On cloudy day, heat radiations coming from the Sun do not reach the solar water heater. [/solution]...
Give the names of two energy sources that you would consider to be exhaustible.
[question] Question. Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices. [/question] [solution] solution: (1) Coal (2) Petroleum Both these sources are present only in limited amounts and will be exhausted soon if we continue to use them at the present rate. These sources were formed over millions of years under special circumstances. [/solution]...
Name two energy sources that you would consider to be renewable.
[question] Question. Name two energy sources that you would consider to be renewable. Give reasons for your choices. [/question] [solution] solution: (1) Water energy (hydro-energy), water on Earth can be used again and again to generate hydro energy as it is stored again and again in dams due to the water cycle that exists in nature. (2) Bio-mass energy, bio-mass can be managed by replacing the trees that have been cut down for fire-wood, cattle dung will be available as long as life exists on ...
Hydrogen has been used as a rocket fuel.
[question] Question. Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG ? Why or why not ? [/question] [solution] solution: Hydrogen is a cleaner fuel than CNG. This is because it produces water on burning whereas $\mathrm{CNG}$ on burning, produces $\mathrm{CO}_{2}, \mathrm{H}_{2} \mathrm{O}$ and $\mathrm{CO}$. [/solution]...
Can any source of energy be pollution-free ?
[question] Question. Can any source of energy be pollution-free ? Why or why not ? [/question] [solution] solution: No source of energy is totally pollution-free, only the degree and the manner of pollution vary. For example, solar cells seem to be non-polluting but environmental pollution is caused in the manufacturing of solar cells. [/solution]...
What are the advantages of nuclear energy ?
[question] Question. What are the advantages of nuclear energy ? [/question] [solution] solution: (1) The mass of nuclear fuel like uranium-235 required is extremely small as compared to a fossil fuel to produce the same amount of energy. (2) In a nuclear power plant, the nuclear fuel supplies energy over a long period of time. [/solution]...
What is geothermal energy ?
[question] Question. What is geothermal energy ? [/question] [solution] solution: The heat energy inside the earth's crust is known as geothermal energy. The geological changes in some regions push the hot magma upwards which gets collected at some depth below the surface of earth. Such places are called hot spots. These hot spots serve as a source of heat energy (or geothermal energy). The geothermal energy is utilised to convert water into steam which rotates a steam turbine. [/solution]...
What are the limitations of energy
[question] Question. What are the limitations of energy that can be obtained from the oceans ? [/question] [solution] solution: The energy obtained from the oceans is (1) tidal energy, for which very few suitable sites are available for construction of dams and the generation is intermittent and not very large. (2) sea-waves energy, where power output is variable and the currently available technologies are quite expensive. (3) ocean thermal energy, where the conversion efficiency is quite low b...
What kind of mirror - concave,
[question] Question. What kind of mirror - concave, convex or plane - would be best suited for use in a solar cooker ? Why? [/question] [solution] solution: A concave mirror is best suited for use in a solar cooker. This is because a concave mirror concentrates solar energy from over a large area into a small area (at its focus). As a result, high temperatures can be achieved. Such a mirror is called solar concentrator. [/solution]...
How has the traditional use of wind and water
[question] Question. How has the traditional use of wind and water energy been modified for our convenience ? [/question] [solution] solution: The traditional use of wind energy has been modified by using windmills (or wind turbines) and that of water by constructing hydro power plants. [/solution]...
Why are we looking at alternate sources of energy?
[question] Question. Why are we looking at alternate sources of energy? [/question] [solution] solution: Fossils fuels were formed due to extraordinary circumstances that took place millions of years ago. No new reservoirs of these fuels are being formed due to the absence of those circumstances. Thus, they are non-renewable sources of energy. If we continue to use these sources at the present rate, we would soon be deprived of these sources. That is why, we are looking for alternate sources of ...
What are the disadvantages of fossil fuels ?
[question] Question. What are the disadvantages of fossil fuels ? [/question] [solution] solution: Fossil fuels (coal, petroleum and natural gas) have the following disadvantages : (1) The fossil fuels are non-renewable sources of energy, if we continue to consume these sources at alarming rates, we would soon run out of energy. (2) There are no such alternate sources of energy developed till today which can replace fossil fuels. Thus, large dependency on fossil fuels for most of our energy requ...
If you could use any source of energy for heating your food,
[question] Question. If you could use any source of energy for heating your food, which one would you use and why ? [/question] [solution] solution: We would use a microwave oven for heating the food as it heats uniformly and cleanly without loss in its nutritional value. Also, we can use solar cooker if bright sunlight is available because the nutrients are not lost during heating in solar cooker. [/solution]...
What is a good fuel ?
[question] Question. What is a good fuel ? [/question] [solution] solution: (1) It should have a high calorific value [calorific value is defined as the number of heat units produced when unit mass of fuel is burnt] Thus, a good fuel should liberate more heat per unit mass. (2) It should have low moisture content. (3) It should have low non-combustible matter like ash, etc. That is, it should leave low ash and other residual matter after combustion. (4) Its products of combustion should not be h...
What is a good source of energy ?
[question] Question. What is a good source of energy ? [/question] [solution] solution: A good source of energy should be (1) Capable of doing large amount of work per unit mass or volume. (2) Easily accessible i.e., it should be convenient to use. (3) Easy to transport and store. (4) Capable of delivering desired quantity of energy at a steady rate over a long period of time. (5) Should be economical. [/solution]...