Lakhmir Singh Physics Class 10 Solutions Page No:130
Question 1: Name the product of petroleum that is used to drive heavy vehicles.
Solution : Diesel.
Question 2: Give one example of a good domestic fuel.
Solution : LPG.
Question 3: Name any one hydrocarbon fraction obtained during the fractional distillation of petroleum which is used as a domestic fuel.
Solution : Kerosene.
Question 4: What are the various fuels which are used to generate electricity in a thermal power plant ?
Solution : Coal, oil or gas.
Question 5: Name any four fractions obtained from petroleum which are used as fuels.
Solution : Fractions obtained from petroleum:
Diesel, petrol, kerosene, petroleum gas etc.
Lakhmir Singh Physics Class 10 Solutions Page No:131
Question 6: What is the composition of liquefied petroleum gas (LPG) ?
Solution : LPG consists mainly of butane, alongwith smaller amounts of propane and ethane.
Question 7: Which gaseous fuel is being used increasingly in transport vehicles like cars and buses these days ?
Solution : Compressed Natural Gas (CNG)
Question 8: Write the full form of : (I) LPG, and (ii) CNG.
Solution : (i) LPG-Liquified Petroleum Gas.
(ii) CNG-Compressed Natural Gas.
Question 9: What is the main constituent of :
(i) petroleum gas ?
(ii) natural gas ?
Solution : (i) Main constituent of petroleum gas is butane.
(ii) Main constituent of natural gas is methane.
Question 10: Name the component which is found in natural gas as well as in biogas.
Solution : Methane.
Question 11: State two important uses of natural gas.
Solution : Uses of natural gas:
(i) As a fuel in thermal power plants.
(ii) As a fuel in transport vehicles.
Question 12: State one important use of CNG these days.
Solution : CNG is used as a fuel in transport vehicles.
Question 13: Complete the following sentence :
Domestic gas cylinders like Indane contain mainly………..
Solution : butane.
Question 14: Explain why, natural gas is considered to be a good fuel.
Solution : Natural gas is considered to be a good fuel because it has a high calorific value, burns with a smokeless flame, causes no air pollution and does not produce any poisonous gas.
Question 15: What is meant by conventional sources of energy ? Write the names of two conventional sources of energy.
Solution : The traditional sources of energy which are familiar to most people are called conventional source of energy.
Ex. Wood, coal etc.
Question 16: Explain the principle of working of a thermal power plant. Draw a labelled diagram to illustrate your answer.
Solution : In a thermal power plant, heat produced by burning coal is used to boil water to form steam. The steam, at high temperature and pressure, rotates the turbine and its shaft, which drives the generator to produce electricity.
Question 17: What are the disadvantages of burning fossil fuels ?
Solution : Disadvantages of burning the fossil fuels are:
(i) The burning of fossil fuels produce acidic gases.
(ii) The burning of fossil fuels produce large amount of CO2 gas, which increases greenhouse effect.
(iii) The burning of fossil fuels produce smoke and leaves behind a lot of ash.
Question 18: Write a short note on the pollution caused by burning fossil fuels.
Solution : Burning of fossil fuels leads to the production of many acidic gases like sulphur-dioxide and nitrogen dioxides. These gases causes acid rain which damages trees, plants and buildings, reduces fertility of soil, and poses danger to aquatic life. The burning of fossil fuels puts a poisonous gas carbon monoxide in air. It also produces large amount of CO2 gas which damages the environment in the long run by increasing the greenhouse effect. Also, burning of fossil fuels produces smoke and a lot of ash.
Question 19: What are the various steps which can be taken to control (or reduce) pollution caused by burning fossil fuels ?
Solution : Pollution caused by the burning of fossil fuels can be controlled by the increasing the efficiency of combustion process and by using various techniques to reduce the escape of harmful gases and ash into the surrounding air.
Question 20: If you could use any source of energy for heating your food, which one would you use and why ?
Solution : We will use LPG due to its high calorific value and smokeless flame.
Question 21: Why is LPG considered a good fuel ?
Solution : LPG is considered as good fuel because it has a high calorific value gives a smokeless flame.
Question 22: Why is LPG considered a better fuel than coal ?
Solution : LPG is considered as a better fuel than coal because it has a higher calorific value, while burning it does not produce any smoke.
Question 23: Why is the leakage of LPG detected easily although it is odourless ? State the steps to be taken in case its leakage is detected in the kitchen.
Solution : For the detection of leakage, a foul smelling substance called ethyl mercaptan is added to the LPG.
In case of LPG leakage in the kitchen, following steps must be taken:
1. The door and windows should be opened at once to allow the gas to escape.
2. The source of gas leakage should be checked and then set right with the help of a gas mechanic.
Question 24: (a) What are fossil fuels ? Give three examples of fossil fuels.
(b) Describe how fossil fuels were formed.
(c) Explain how, sun is considered to be the ultimate source of fossil fuels.
(d) Which fossil fuels were formed by the buried remains of small plants and animals ?
(e) Which fossil fuel was formed by the buried remains of large land plants ?
Solution : (a) Natural fuels formed deep under the earth from the pre-historic remains of the organisms (like plants and animals) are called fossil fuels.
Ex. Coal, petroleum and natural gas.
(b) The plants and animals which died millions of years ago and got buried deep in the earth, away from the reach of oxygen, got converted into fossil fuels due to the chemical effects of pressure, heat and bacteria.
(c) Sun is considered to be the ultimate source of fossil fuels because it was the sunlight of long ago that made plants grow and the animals which got buried in the earth also ate plants. So, plants and animals which were originally made by sun’s energy only have been converted into fossil fuels.
(d) Petroleum and natural gas.