How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?
As an individual we should make the contribution and some differences for the management of Forests and wildlife, water resources and coal petroleum. Some approaches we should use for the conservation.
Forest and Wildlife:
1. We should promote Afforestation programs instead of promoting deforestation. Deforestation is the clearing of forest to claim the land that will be used by the man. It affects the soil fertility, increase soil erosion, floods and droughts have become more frequent, landslides increases etc. So, to overcome these effects, afforestation program should be applied which means to grow plants, i.e, plantation.
2. We should minimise the use of timber and instead of that we should use the alternative source of energy like biogas, supplement the fuel wood. Forest fires should be prevented; pests and diseases of the forest trees should be controlled.
3. Overgrazing should be prohibited; uses of modern techniques should be adopted like irrigation, fertilizers, control of weeds, breeding of choice trees and tissue culture etc.
Water Resources:
1. We should promote rain- water harvesting.
2. Close the taps while we are brushing our teeth, shaving or bathing when the bucket gets filled.
3. We should avoid the throwing of waste like plastic bottles, polythene, glasses in the beaches, lakes, ponds etc, that are polluting our water.
4. Several waste water treatment methods have been given like Bioreactors, Trickling filter method, Activated Sludge Method, treatment of Industrial Effluents etc.
Coal and Petroleum:
1. Use the bicycle to go to the short distances instead of using scooty, cars, or another automobiles which are running on petrol.
2. We should not use coal as a fuel.
3. We should use the alternative energy sources like hydro- energy power plant and solar energy instead of using coal or petroleum because they affect our environment and our health too. They produce large amount of smog by burning them and produce very foul smell which affects our health by inhaling them.
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Outline a project which aims to find the dominant coat colour in dogs.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
How is the sex of the child determined in human beings?
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
Calculate the number of electrons constituting one coulomb of charge.
What is an homologous series? Explain with an example.
Why is variation beneficial to the species but not necessarily for the individual?
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
Find out, from Table 10.3, the medium having highest optical density. Also find the medium with lowest optical density.
Material medium |
Refractive index |
Material medium |
Refractive index |
Air | 1.0003 | Canada Balsam |
1.53 |
Ice | 1.31 | ||
Water | 1.33 | Rock salt | 1.54 |
Alcohol | 1.36 | ||
Kerosene | 1.44 | Carbon disulphide |
1.63 |
Fused quartz |
1.46 | ||
Turpentine oil |
1.47 | Ruby | 1.71 |
Benzene | 1.50 | Sapphire | 1.77 |
Crown glass |
1.52 | Diamond | 2.42 |
Table 10.3 Absolute refractive index of some material media
Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
Which of the following terms does not represent electrical power in a circuit?
(a) I2R (b) IR2 (c) VI (d) V2/R
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?
An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position of the image, its nature and size.
People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes?
What precaution should be taken to avoid the overloading of domestic electric circuits?
Give any two ways in which biodegradable substances would affect the environment.
What is the role of the acid in our stomach?