SCIENCE CLASS 8 CHAPTER 5 COAL AND PETROLEUM EXERCISES Question no. 1 What are the advantages of using CNG and LPG as fuels? Answer no. 1 There are so many advantages of using CNG and LPG as fuel 1. CNG and LPG are clean fuels and they do not release smoke, hence reduce the pollution. 2. CNG and LPG can be transported easily through pipelines. 3. CNG and LPG burn easily. 4. CNG and LPG gives a lot of heat energy when burnt. Question no. 2 Name the petroleum product used for surfacing of roads. Answer no. 2 Bitumen is used for surfacing of roads. Question no. 3 Describe how coal is formed from dead vegetation. What is this process called? Answer no. 3 The earth had dense forests in low lying wetland areas. Due to natural processes, such as flooding, these forest got buried under the soil. More and more soil got deposited over them and and they got compressed more. The temperature also rose as they went deeper and deeper. Und...

SCIENCE CLASS 8 CHAPTER - 4 MATERIALS : METALS AND NON METALS EXERCISES Question no. 1 Which of the following can be beaten into thin sheets? a-  Zinc                 b-  Phosphorus               c-  Sulphur          d-  Oxygen Answer no. 1 a-  Zinc Question no. 2 Which of the following statement is correct ? a-  All metals are ductile b-  All non metals are ductile c-  Generally, metals are ductile d-  Some non metals are ductile Answer no. 2 c- Generally, metals are ductile Question no. 3 Fill in the blanks a-  Phosphorus is a very _________________ non metal. b-  Metals are _________________ conductors of heat and __________________ . c-  Iron is ___________________ reactive than copper d-  Metal react with acid to produce ___________________ ...

SCIENCE CLASS 8 SYNTHETIC FIBRES AND PLASTICS EXERCISES Question number 1 Explain why some fibres are called synthetic. Answer number 1 Some fibres are called synthetic fibres because these are man made fibres prepared by using chemical substances. Synthetic fibres are nylon, rayon, acrylic, polyester etc. Question number 2 Mark (√) the correct answer: Rayon is different from synthetic fibres because (a) it has a silk like appearance (b) it is obtained from wood pulp (c) its fibres can also be woven like those of natural fibres Answer number 2 (b) it is obtained from wood pulp. Question number 3 Fill in the blanks with appropriate words: (a) Synthetic fibres are also called ______ or _______ fibres. (b) Synthetic fibres are synthesised from raw material called ________. (c) Like synthetic fibres, plastic is also a __________ . Answer number  3 (a) artificial, manmade (b) petrochemicals (c) polymer Question number 4 Give examples which indi...

SCIENCE CLASS-8  CHAPTER -2   MICROORGANISMS - FRIEND AND FOE   EXERCISES Question number 1 Fill in the blanks. (a) Microorganisms cam be seen with the help of a __________________. (b) Blue green algae fix ________________ directly from the air to enhance fertility of soil. (c) Alcohol is produced with the help of ________________. (d) Cholera is caused by __________________. Answer number 1 (a) microscope. (b) nitrogen. (c)yeast. (d)bacteria. Question number 2 Tick the correct answer. (a) Yeast is used in the production of  (i)sugar (ii)alcohol (iii)hydrochloric acid (iv)oxygen (b) The following is an antibiotic (i)sodium bicarbonate (ii)streptomycin (iii)alcohol (iv)yeast (c) Carrier if malaria - causing protozoan is (i)female anopheles mosquito (ii)cockroach (iii)housefly (iv)butterfly (d) The most common carrier of communicable diseases is (i)ant (ii)housefly ...

CLASS 8 SCIENCE CROP PRODUCTION AND MANAGEMENT EXERCISES QUESTION NO. 1 1.  Select the correct word from the following list and fill in the blanks.     float, water, crop, nutrients, preparation (a) The same kind of plant grown and cultivated on a large scale at a place is called _____________ (b) The first step before growing crops is ____________ of soil. (c) Damaged seeds would ___________ on the to of water. (d) For growing a crop, sufficient sunlight and _____________ and ______________ from the soil essential. ANSWER NO. 1 (a) crop (b) preparation (c) float (d) water, nutrients QUESTION NO. 2 2. Match items in column A with those in column B                  A                                             B (i)Kharif crops          ...