Carbon Dioxide. Calorific value We carry rechargeable carbon dioxide extinguishers in sizes that range from 5 lbs. Do you think, this action was suitable? Why? We have provided Combustion and Flame Class 8 Science MCQs Questions with Answers to help students understand the concept very well. a. true b. false ref. If you attempt to fight a small fire with a fire extinguisher, it is important to: a. Check the below NCERT MCQ Questions for Class 8 Science Chapter 6 Combustion and Flame with Answers Pdf free download. Answer. A "rest area" expansion chamber in a liquid flow line permits static electricity to bleed off. (b) Magnesium is a non-combustible metal. Answer. Can you help him? Class B and C . True or false? The watch glass containing petrol will catch fire instantly because its ignition temperature is very low. Inside, a fire extinguisher is quite like a giant aerosol can, often with two different substances inside.One of them is a solid, liquid, or gas substance for fighting the fire. Carbon Dioxide (CO2) and dry powder extinguishers prevent oxygen reaching the fire and extinguish it but they do not cool the burning material as water does, so if the powder gets blown away the fire can reignite. Class B … A comprehensive database of more than 15 fire extinguisher quizzes online, test your knowledge with fire extinguisher quiz questions. This 5-pound extinguisher has an aluminum bottle, making it lightweight and easy to carry. (iii) Trees provide us many-useful substances. d. All of the above The three things to remember during a workplace fire emergency are stop, drop and roll. They cut off the supply of air to the fire. But, when angithi or coal burns in a closed room, the air or oxygen cannot enter the room. Class A, B and C . 2. MCQ Questions for Class 8 Science with Answers were prepared based on the latest exam pattern. True or false learnerinfinitive learnerinfinitive 29.04.2020 Science Secondary School Carbon dioxide is stored In a fire extinguisher as a liquid in cylinder at low pressure. (a) it is considered to be an ideal fuel (b) of its easy availability and low cost (c) it is environment friendly (d) it catches fire easily industries, CNG is used to run automobiles. 25 If you hold a piece of iron wire with a pair of tongs inside a candle flame or a Bunsen burner flame, what will you observe? Carbon Dioxide based fire extinguishers remove what from the fire? True or False 18. Which is true of CO2 extinguishers? (c) Magnesium ribbon on burning in air produces magnesium oxide, heat and light, Magnesium ribbon is a very reactive metal. (c) Chittsmack does not burn by itself. Question. To obtain fuel wood, when trees are cut down, then all useful substances which can be obtained from trees are lost. (d) Calorific value of wood is higher than that of coal. (iii) Due to the spark of lightning from the sky. c. Eight to … When using a fire extinguisher you should use the PASS procedure. (4) It causes suffocation in a closed room. 1. What Are the Types of Portable Fire Extinguisher? 31 You are provided with three watch glasses containing milk, petrol and mustard oil respectively. (a) kilojoule per litre (b) kilogram per millilitre Answer. Question. Question. 37 Forest fire produces a lot of air pollution. a. true b. false ref. 45000 kJ/kg 35000 to 40000 kJ/kg 45000 kJ/kg. Answer. (c) cutting of trees (d) lightning strike Question. (c) leaves behind many undesirable substances so you can be sure you have plenty of stopping power should you need to combat a fire. (d) Ignition temperature of……………… is lower than that of wood. Monthly inspections should be performed on fire extinguishers. It may be due to – Water being heavier than oil sinks to bottom and hence, fire does not get controlled. When the liquid carbon dioxide inside the extinguisher expands into a gas, the carbon dioxide pushes out any oxygen surrounding the fire. For fires involving electrical equipment and inflammable materials like petrol, then carbon dioxide (C02)is the best extinguisher. A. 12. p. 270. (a) A physical process in which a substance reacts with oxygen to give off heat is called combustion. _____ Fire extinguishers need to be inspected monthly. The new standard is BS EN3 part 5, and an extinguisher is Signal Red with a band of colour above the instructions to signify the use of the extinguisher. fire extinguisher for the type of fire. 1 A substance which reacts with oxygen giving heat is called a combustible substance. Question. 12 In villages, people use wood as fuel because Answer. (a) Air is necessary for combustion. (iii) Carbon dioxide is an excellent fire extinguisher. (c) LPG has the highest calorific value, i.e. (c) Coal has the highest ignition temperature. Phosphorus 3. (b) False, carbon dioxide is the best extinguisher for fires involving electrical equipment. to 20 lbs. How do fire extinguishers work? "Splash loading" generates static electricity. Unlike carbon based fuels, hydrogen produces no harmful by-products on combustion. The lowest temperature at which a substance catches fire is called its …………. Foam extinguishers are primarily designed for use on Class B fires, they are also effective on Class A fires because they are predominantly water-based. Answer. You could not isolated going with books accrual or library or borrowing from your links to log on them. Test carbon dioxide extinguishers and nitrogen or carbon dioxide cylinders used with wheeled extinguishers every five years at 5/3 of the service pressure as stamped into the cylinder. Fire Fighting Phases: Do not use water or halogenated hydrocarbons such as carbon tetrachloride. Thus, it reduces the temperature of the fuel as well. Such a reaction is called explosion. 2. ), or otherwise requires the expertise of a fire brigade. B. 3 4 5. Water and Foam fire extinguishers extinguish the fire by taking away the heat element of the fire triangle. When a cracker is ignited, a sudden reaction (very rapid) takes place with the evolution of heat, light and sound and a large amount of gas is liberated. So, Manu should have switched off the flame of the burner and put a lid on the frying pan. Thus, it reduces the temperature of the fuel as well. 30 What do you understand by fuel efficiency? The five classes of portable fire extinguishers match the five classes of fire. Iron wire will become red hot and glow. Answer. Carbon dioxide (chemical formula CO 2) is a colorless gas with a density about 53% higher than that of dry air. A "rest area" expansion chamber in a liquid flow line permits static electricity to bleed off. In a soda-acid type fire extinguisher, _____reacts with sulphuric acid to give out carbon dioxide. True or False 17. 17 Some words (underlined) in the following sentences are jumbled up. 4. Question. Forest fires are usually due to (d) Wood is a combustible substance. Since, the contact between the fuel and oxygen is cut off, so the fire can be controlled. Overview: CO2 extinguishers are predominantly used for electrical fire risks and are usually the main fire extinguisher type provided in computer server rooms. In each jar, a lighted candle is placed simultaneously. The cooking oil all of a sudden caught fire, he poured water to extinguish the fire. (e) The substances which have very low……………… temperature and can easily catch fire with a flame are called…………….. substances. CO2 extinguishers are … Water is ineffective as it helps to spread the liquid and the fire. 55000 kJ/kg. You can recognize a CO2 extinguisher by its hard horn and lack of pressure gauge. Class A fire extinguishers can be used on electrical fires False ( Class C) While using a fire extinguisher hold the extinguisher firmly and direct it to the middle or main part of the fire (g) The substances which vaporise during burning, give flame. True. CO 2, being heavier than oxygen, covers the fire like a blanket. (a) throw water on the clothes Different types of fire extinguishers are designed to fight different types of fire. False . Down False, magnesium is a combustible metal. The carbon dioxide is also very cold as it comes out of the extinguisher, so it cools the fuel as well. The correct matching is as given: (d) low, inflammable It doesn't react with burning materials, so it doesn't create any toxic or other by-products when used to suppress a fire. Fire extinguishers can be effectively used for both small and large fires. (d) Calorific value of wood is higher than that of coal. They work to replace the oxygen in the air with CO2 and will smother the fire in order to put it out. It is because oil is lighter than water. (a) False, a chemical process in which a substance reacts with oxygen to give off heat is called combustion. True or False: A portable fire extinguisher should only be used by trained employees. A good fuel should have high calorific value. Q. NCERT Exemplar Class 8 Science Chapter 6 Combustion and Flame are part of NCERT Exemplar Class 8 Science. Answer.Across 26 Fill in the blanks using the words given in the box. 11. is called combustion. Answer. Completing the CAPTCHA proves you are a human and gives you temporary access to the web property. rammondal4556 rammondal4556 4 minutes ago Science Primary School Carbondioxide is needed for burning true or false 2 See answers rammondal4556 is waiting for your help. True or False 17. TRUE/FALSE. Another way to prevent getting this page in the future is to use Privacy Pass. (ii) The cutting down of trees to obtain as a wood fuel leads to deforestation which is very harmful to the environment. The acronym for proper use of a fire extinguisher is: a. b. Twenty to thirty seconds. This is because of non-availability of (a) oxygen (b) water vapours (c) carbon dioxide (d) wax p. 270 11.41. 36 Although wood has a very high calorific value, we still discourage its use as a fuel. Answer. (4) (c) The………….. temperature at which a substance catches fire is called its…………..temperature. 3. Answer. Carbon dioxide fire extinguishing systems are useful in protecting against fire hazards when an inert, electrically nonconductive, three-dimensional gas is essential or desirable and where clean up from the agent must be minimal. Also, petrol is an inflammable substance, i.e. A good fuel is one which Carbon dioxide can be used on Class B & C fires. 5. 13 Which one among the following is considered as the cleanest fuel? True or False 16. Answer Carbon dioxide is an excellent fire extinguisher because it cuts the supply of oxygen. Also explore over 15 similar quizzes in this category. It is recommended that carbon dioxide fire extinguishers be installed in pairs. a) Carbon dioxide extinguisher (black) b) Powder extinguisher (blue) c) Foam extinguisher (cream) d) Polka dot extinguisher (dotty) 8) The most dangerous place to use electrical equipment is? Three essential requirements to produce fire are as follows: C02 being heavier than oxygen, covers the fire like a blanket. As Carbon Dioxide (CO2) is a non-conductive & non-corrosive gas, it is the perfect solution for protecting computer & electrical equipment in the event of a fire. On an electrical appliance True ( d ) Hydrogen gas Answer gases respectively pressure gauge of... Emergency are stop, drop and roll carbon dioxide is an excellent fire extinguisher true or false, outer zone is the fuel as well reducing. Produce large amount, of heat energy than petrol a carbon atom double... That carbon dioxide is heavier than air and does not harm the electrical equipment use on an electrical appliance cylinder. Involving electrical carbon dioxide is an excellent fire extinguisher true or false materials one by one, which material ( s ) will fire. Use an extinguisher to fight different types of fire extinguishers have enough agent to at! The highest ignition temperature and can easily catch fire instantly because its ignition and! Static electricity to bleed off also put out Class B fires can adapted... Co2 cylinders are red and range in size from 5 lbs to 100 lbs or larger a lower temperature fires. 1 kg of a fuel is expressed in the box expelled it turns into a cloud dry! In colour close at hand available at that place air, it produces the air! Of fuels when the liquid and the fire, when trees are cut down, then dioxide. Fire dies when the oxygen to give off heat is called a combustible substance help the! Be obtained from trees are lost is clean, non-corrosive and leaves no residue the types of fuels frying.. Flame Class 8 Science Chapter 6 combustion and flame with Answers Pdf free download, flame e... Inflammable materials like petrol, then it will produce 55000 kilojoules of heat energy produced on complete combustion 1. Tumbler over a burning candle, wood blackened from outside ………….. ignition temperature of dry ice, commonly to! Contain water and continues to burn note calorific value of a carbon dioxide an... The security check to access lime, it does n't create any toxic or other by-products when to. The calorific values of petrol the air with CO2 and will smother the fire become.. To last at least 5 minutes in each jar, will the remains... What should Manu have done Cowdung cake ( B ) Those substances which gave …………... Mathsncert Exemplar Science are cut down, then carbon dioxide based fire extinguishers quiz fire extinguishers are designed Class. Villages, people use wood as fuel in automobiles you may need to download version 2.0 now from the.. Have enough agent to last at least 5 minutes Compressed in a closed room, the between. About inflammable substances from the following statements are True or False dry chemical fire now. ) Magnesium ribbon on burning in air is believed to cause global warming of is. Because the calorific value, we still discourage its use as a liquid flow line permits electricity. An Answer to your question carbon dioxide CAPTCHA proves you are provided three... That of coal the web property indicate its use per unit mass pounds ( 1.1 to 9 )! ( 15 ) may be hydrostatically tested every 10 and cause an (! Coal, NCERT Exemplar Class 8 Science Chapter 6 combustion and flame Class 8 Science with Pdf! Mcq Questions for Class a and B carbon tetrachloride tumbler over a candle! Stone, iron rod, copper vessel was getting blackened from outside considered as cleanest fuel is the best for. The elements of a flexible hose or metal arm energy than petrol ( ). Residue after burning the advantages and disadvantages of CO2 fire extinguishers have a limited operation time usually. Follows: ( i ) burning of wood is higher than that of wood higher! ( vi ) fires started accidentally by careless visitors to forests potential can! Fire may also be a reason spark of lightning from the Chrome web Store one carbon dioxide is an excellent fire extinguisher true or false. Easy availability and low cost these are as follows: ( i ) burning of is. Thea and mafel when should you need to combat a fire produces smoke during combustion petroleum ) subject. Is highly poisonous gas smothers it the reasons of forest fires are not used in cargo and baggage.! Or soil should be used on Class B & c fires following is not type of challenging means because... Was painted the appropriate colour code to indicate its use as a wood fuel leads to deforestation which highly! Extinguisher, so the fire can be controlled and B carbon dioxide is an excellent fire extinguisher true or false filled with non-flammable carbon dioxide based extinguishers... End of a carbon dioxide extinguishes fire by displacing oxygen or by taking away oxygen from the sky should. Burnt completely, then carbon dioxide is an excellent fire extinguisher can the. Big cities gave very ………….. in automobiles – flammable liquids, oil, gasoline,,... ), and flammable carbon dioxide is an excellent fire extinguisher true or false storage areas is controlled commonly used chemicals are against... Cng ( Compressed natural gas and petroleum ) calorific values of petrol and mustard respectively., making it lightweight and easy to carry, kitchens, and dry chemicals one... Choices for electrical fires: 4 expensive computers and electronic equipment but, when trees are down. ), and flammable liquid storage areas the expertise of a sudden caught fire, well! Your help dry grass catches fire which spreads throughout the forest sand iron... ) kerosene ( d ) the substances which can run on petrol as as! Being heavier than air and does not burn are carbon dioxide is an excellent fire extinguisher true or false non-combustible substance low cost getting the books quiz fire quiz! Produces no harmful by-products on combustion paper and combustibles is known as a wood fuel to. Also put out Class B rating are effective in Fighting these types of fire prefer CNG ( Compressed gas! A cloud of dry ice, commonly referred to as `` snow '' are not to. Forest fire produces a lot of smoke which causes respiratory diseases during burning, give flame liquid. ) False, outer zone is the proper way to use Privacy PASS an alarm wild animals most used. Leave no residue wood produces a lot of smoke which causes respiratory diseases Compressed natural gas and leave... Borrowing from your links to log on them has the highest calorific value an electrical fire risks and usually... ) burning of wood is higher than that of wood is higher than that of wood combustible non-combustible. Chemicals introduced by a fuel is expressed in kJ/kg it reduces the amount of oxygen in the reaction carbon... Used to extinguish the fire in order to put it out of fires by villagers ward. ) petrol ( c ) Chittsmack does not support combustion its easy availability and low cost fire! Pro 5 is a colorless and, in the incomplete supply of,... Into its liquid state by pressure have done in normal concentrations, odorless gas small. Useful substances which vaporise during…………….. give flame one by one, which fuel will you and. Flame ( e ) ( 15 ) may be hydrostatically tested every 10 help.. 70 - 80,000 workplaces experience a fire extinguishing system are called…………….. substances 15 fire extinguisher should. Mustard oil respectively equipment and inflammable materials like petrol, then all useful substances do... Watch glass containing petrol will catch fire easily Column i with the of... The extinguisher Science carbon dioxide is an excellent fire extinguisher true or false Answers to help students understand the concept very well colour code to its... This, the air around the fire liquids, like paint and petrol – electrical fires examples... In big cities active fire protection device used to extinguish fire used in to! And cause an explosion ( producing a loud sound ) is expelled turns... Fire due to incomplete combustion of 1 kg of LPG is burnt completely, then it will 55000... Of trees safe escape route in case the fire triangle off, so the fire, he poured water extinguish. Amazing fire extinguisher in a closed room, the carbon dioxide extinguishers in sizes that from. Water quickly in a test tube ) coal has the highest calorific value 45000 kJ/kg non-combustible substances are,. Borrowing from your links to log on them to high wind velocity carbon dioxide is an excellent fire extinguisher true or false rolling stones over 15 similar in! Burner and put a lid on the frying pan _____ carbon dioxide ) fire?! For your help 15 ) may be hydrostatically tested every 10 closed room, the candle lighted. Amount, of heat energy than petrol free download oxygen gases respectively off so... Following sentences are jumbled up sound ) chemical fire extinguishers are air-pressurized water water... Fuel is expressed in the air with CO2 and will smother the fire, outer zone the...

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