What are the environmental consequences of the increasing demand for energy? What steps would you suggest to reduce energy consumption?
Due to Industrialisation the demand for energy increases . Fossil fuels are easily accessible sources of energy that fulfil this demand. The increased use of fossil fuels has an adverse effect on the environment. Large consumption of fossil fuels increases the greenhouse gas in the atmosphere, resulting in global warming and a rise in the sea level.
It is not possible to reduce the consumption of fossil fuels. However, some preventive measures can be taken such as using electrical appliances wisely and not wasting electricity. Unnecessary usage of water should be avoided. Public transport systems with mass transit must be adopted on a large scale. These small steps may help in reducing the consumption of natural resources and conserving 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?
What are plant hormones?
How are the areas of study – evolution and classification – interlinked?
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?
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not?
Several electric bulbs designed to be used on a 220 V electric supply line, are rated 10 W. How many lamps can be connected in parallel with each other across the two wires of 220 V line if the maximum allowable current is 5 A?
What chemical process is used for obtaining a metal from its oxide?
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.
(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.
The refractive index of diamond is 2.42. What is the meaning of this statement?
Why is DNA copying an essential part of the process of reproduction?
Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V each, a 5 Ω resistor, an 8 Ω resistor, and a 12 Ω resistor, and a plug key, all connected in series.