What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?
Solar cooker uses the Sun's energy to heat and cook food. It is an inexhaustible and clean renewable source of energy. It is free for all and available in unlimited amounts. Hence, operating a solar cooker is not expensive.
Disadvantage of a solar cooker is that it is very expensive. It does not work without sunlight. Hence, on cloudy days, it becomes useless.
The places where the days are too short or places with cloud covers round the year, have limited utility for solar cookers.
Can any source of energy be pollution-free? Why or why not?
What are the limitations of the energy that can be obtained from the oceans?
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?
Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?
Which of the following is not an example of a bio-mass energy source?
(a) wood (b) gobar-gas
(c) nuclear energy (d) coal
What are the disadvantages of fossil fuels?
Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.
Name two energy sources that you would consider to be renewable. 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?
Why does distilled water not conduct electricity, whereas rain water does?
Why do you think that there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
What is hydrogenation? What is its industrial application?
What will be the formula and electron dot structure of cyclopentane?
What is the function of digestive enzymes?
A solution turns red litmus blue, its pH is likely to be
(a) 1 (b) 4 (c) 5 (d) 10
Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.
Explain the formation of scum when hard water is treated with soap.
Explain the meanings of malleable and ductile.