What are the advantages of nuclear energy?
The nuclear energy advantages are as follows:
a) Fusion of four hydrogen atoms produces a huge amount of energy approximately equal to 27 MeV.
b) Large amount of energy is produced per unit mass.
c) It does not produce smoke. It is clean energy.
d) Fission of one atom of uranium produces 10 million times the energy released by burning of one atom of carbon.
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?
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?
What is a good source of energy?
What are the disadvantages of fossil fuels?
Which of the following is not an example of a bio-mass energy source?
(a) wood (b) gobar-gas
(c) nuclear energy (d) coal
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?
What is the role of decomposers in the ecosystem?
How many 176 Ω resistors (in parallel) are required to carry 5 A on a 220 V line?
State Fleming’s left-hand rule.
Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as
(a) Na (b) Mg (c) AI (d) Si
What determines the rate at which energy is delivered by a current?
The kidneys in human beings are a part of the system for
(a) nutrition. (c) excretion.
(b) respiration. (d) transportation.
How are the lungs designed in human beings to maximise the area for exchange of gases?
A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet is (i) pushed into the coil, (ii) withdrawn from inside the coil, (iii) held stationary inside the coil?
What is a neutralisation reaction? Give two examples.
Judge the equivalent resistance when the following are connected in parallel – (a) 1 Ω and 106 Ω, (b) 1 Ω and 103 Ω, and 106 Ω.