What are the limitations of the energy that can be obtained from the oceans?
The various forms of energy can be obtained from the ocean these are:
a. ocean thermal energy
b. wave energy and
c. tidal energy
Limitations of Tidal Energy:
i. Limited areas around the world which are suitable for building tidal dams.
ii. During high and low tides the rise and fall of sea-water is not enough to generate electricity on a large scale.
Limitations of Wave Energy:
In the world there are limits where the waves strike the shore lines with sufficient power that is sufficient to generate electric energy from the kinetic energy of the waves.
Limitations of Ocean Thermal Energy:
Ocean thermal plant involves high cost. To convert ocean thermal energy into electricity, a great variation in temperature difference of 20°C (or more) between the surface water of the ocean and deeper water is needed for operating OTEC power plants.
i. Limited areas around the world which are suitable for building tidal dams.
ii. During high and low tides the rise and fall of sea-water is not enough to generate electricity on a large scale.
Can any source of energy be pollution-free? Why or why not?
If you could use any source of energy for heating your food, which one would you use and why?
What is a good source of energy?
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?
Which of the following is not an example of a bio-mass energy source?
(a) wood (b) gobar-gas
(c) nuclear energy (d) coal
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
What are the disadvantages of fossil fuels?
Compare and contrast fossil fuels and the Sun as direct sources of energy.
Name two energy sources that you would consider to be renewable. Give reasons for your choices.
Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
Do basic solutions also have H+(aq) ions? If yes, then why are these basic?
What processes would you consider essential for maintaining life?
Give reasons
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
Why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
How is the small intestine designed to absorb digested food?
How are the lungs designed in human beings to maximise the area for exchange of gases?
Describe double circulation of blood in human beings. Why is it necessary?
We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.
Name a mirror that can give an erect and enlarged image of an object.