List any four disadvantages of using fossil fuels for the production of energy.
The four disadvantages of using fossil fuels for the production of energy are:
i. It releses high concentration of posinous gases like oxides of sulphur and nitrogen which may cause air pollution and acid rain.
ii. It results in the increase of concentration of Carbon dioxide in the enviroment and hence reults in global warming.
iii. When burnt in less oxygen large amount of toxic gas Carbon monoxide is released which may have adverse effect on the organisms.
iv. They are non-renewable resources of energy, their overuse may lead to depletion of these resources.
What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.
Describe any three ways in which individuals with a particular trait may increase in population.
a) State two properties of carbon which lead to a very large number of carbon compounds.
b) Why does micelle formation take place when soap is added to water? why are micelles not formed when soap is added to ethanol ?
Or
Explain isomerism. State any four characteristics of isomers. Draw the structure of possible isomers of butane C4H10.
a) What is meant by the 'power of a lens'?
b) State and define the S.I. unit of power of a lens.
c) A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with each other.
Calculate the lens power of this combination.
What is binary fission in organisms? With the help of suitable diagrams, describe the mode of reproduction in Amoeba.