3 Magnesium ribbon on burning in air produces CO 2, being heavier than oxygen, covers the fire like a blanket. 32 Manu was heating oil to fry potato chips. Answer. (a) kerosene (b) petrol (c) coal (d) alcohol Dry Chemical. 11. (b) Magnesium is a non-combustible metal. This type of extinguisher is available in several sizes from 2.5 to 20 pounds (1.1 to 9 kilos). Why is it advised to keep the door open? A. industries, CNG is used to run automobiles. A. d. All of the above 1. a. true b. false ref. (a) is readily available Question. Question. For fires involving electrical equipment and inflammable materials like petrol, carbon dioxide (CO 2) is the best extinguisher. Carbon dioxide molecules consist of a carbon atom covalently double bonded to two oxygen atoms. Question. Unlike carbon based fuels, hydrogen produces no harmful by-products on combustion. (a) Cowdung cake (b) Petrol What Are the Types of Portable Fire Extinguisher? The cooking oil all of a sudden caught fire, he poured water to extinguish the fire. They also suppress the fire’s heat because their discharge is very cold. Question. (e) ignition, inflammable 3.True When using a fire extinguisher you should use the PASS procedure. (i) Fuel (combustible substance) (ii) Air (or oxygen) and (c) Forest fires are not due to cutting of trees. 4.False, calorific value of coal is higher than that of wood. Answer. They have 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. (b) In villages, people use wood as fuel because of its easy availability and low cost. 9. That means it should produce large amount , of heat per unit mass. Some of the non-combustible substances are stone, glass, cement, soil, sand, iron nails, etc. (e) The substances which vaporise during……………..give flame. Our online fire extinguisher trivia quizzes can be adapted to suit your requirements for taking some of the top fire extinguisher quizzes. If you have any query regarding NCERT Exemplar Class 8 Science Chapter 6 Combustion and Flame, drop a comment below and we will get back to you at the earliest. Carbon dioxide extinguishers work because carbon dioxide molecules are heavier than oxygen molecules. (d) cover the person with a polythene sheet 3 4 5. (10) Burning of wood has several disadvantages. Question. Answer. PAST b. The most common fire extinguisher is water. 33 What are the three essential requirements to produce fire? standing by. In each jar, a lighted candle is placed simultaneously. (a) Air is necessary for combustion. 2011-11-02 01:11:10 2011-11-02 01:11:10. These are used in . True 12 Class B fires can be extinguished with water, water based agents, and dry chemicals. Water is one of the most commonly used extinguishing agents for ordinary combustibles. Answer. 4. Carbon Dioxide extinguishers are designed for which types of fuels? CO2s may be ineffective at extinguishing Class A fires because they may not be able to displace enough oxygen to successfully put the fire out. If you are on a personal connection, like at home, you can run an anti-virus scan on your device to make sure it is not infected with malware. 1. Each year in the United States 70 - 80,000 workplaces experience a fire. (b) high ignition temperature and can catch fire easily This is an totally easy means to specifically get guide by on-line. Class C fires which involve energized electrical equipment. r. ect. Answer. False. Carbon dioxide extinguishes fire by displacing oxygen or by taking away oxygen from the fire triangle. Question. (ii) Camp fire may also be a reason. 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. cor. You could not isolated going with books accrual or library or borrowing from your links to log on them. A comprehensive database of more than 15 fire extinguisher quizzes online, test your knowledge with fire extinguisher quiz questions. PASS c. PALS d. None of the Above True or False: 4. Have a back-up person. Answer. CO2 extinguishers are … b. (ii) The cutting down of trees to obtain as a wood fuel leads to deforestation which is very harmful to the environment. (c) A good fuel does not produce any harmful gases or leaves any residue after burning. (i) At high temperature, sometimes dry grass catches fire which spreads throughout the forest. The five classes of portable fire extinguishers match the five classes of fire. 3) A fire that is fueled by paper and combustibles is known as a Class "A" fire. (d) Hydrogen gas is considered as cleanest fuel. Class B - Plastics, polyethylene, styrofoam Below is a list of fire extinguisher types matched with surfaces on which they can be used. (d) Ignition temperature of……………… is lower than that of wood. If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. (c) low ignition temperature and can catch fire easily (d) Calorific value of wood is higher than that of coal. b. Twenty to thirty seconds. Water So, in the incomplete supply of oxygen, coal burns to produce carbon monoxide which is highly poisonous gas. True or False 18. This cloud reduces the amount of oxygen in the air around the fire and smothers it. Also write the false statements in their correct form. Question. Question. 34 Give two examples each for a solid, liquid and gaseous fuel along with some important uses. Usual Shipping Containers: Hermetically sealed … In a soda-acid type fire extinguisher, _____reacts with sulphuric acid to give out carbon dioxide. Your IP: 220.127.116.11 Carbon dioxide is heavier than air and does not support combustion. 9 Choose the correct statement about inflammable substances from the following. Answer. They work to replace the oxygen in the air with CO2 and will smother the fire in order to put it out. Water and Foam fire extinguishers extinguish the fire by taking away the heat element of the fire triangle. a. true b. false ref. Where you should not use the carbon dioxide fire extinguishers … It is a clean fuel because it burns without producing smoke. Answer. It only glows on combustion. It will not produce a flame. Answer. Charcoal, chalk, stone, iron rod, copper coin, straw, cardboard, glass, paper, candle, wood. This 5-pound extinguisher has an aluminum bottle, making it lightweight and easy to carry. Question. False, magnesium is a combustible metal. Carbon Dioxide is a heavy gas, commonly stored compressed in a cylinder for use as a fire extinguisher. (b) Magnesium is a non-combustible metal. When they throw away lighted cigarettes in the forest. The job of fire extinguisher is to cut off the supply of air or to bring down the temperature of fuel or both. CO2 is clean, non-corrosive and leaves no residue on expensive computers and electronic equipment. Oxygen. Answer. • (a) kilojoule per litre (b) kilogram per millilitre p. 270 11.40. Write them in theirjrorrect form. CO2s will frequently be found in laboratories, mechanical rooms, kitchens, and flammable liquid storage areas. Question. Use of a carbon dioxide fire extinguisher can subject the user to electrical shock. Class B … Without oxygen available to fuel the chemical reaction, the fire goes out quickly. 5. You can recognize a CO2 extinguisher by its hard horn and lack of pressure gauge. Only energy and clean water are produced. True or false? Do you think, this action was suitable? Note The lowest temperature at which a substance catches fire and starts burning, is called its ignition temperature. The most common fire extinguisher. 3. They don't contain water and won't damage surrounding equipment like powder extinguishers. (f) Middle zone is the hottest zone of a flame. Answer. Question. 7 If a person’s clothes catch fire, the best way to extinguish the fire is to Water being heavier than oil sinks to bottom and hence, fire does not get controlled. We will prefer CNG (Compressed Natural Gas) because the calorific value of CNG is higher than that of petrol. 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. The correct matching is as given: Also write the false statements in their correct form. Can you help him? What is the proper way to use a Class BC, CO2 fire extinguisher? In such situations, soda-acid fire extinguisher does not work as it contains water or uses water to take off fire by cooling down the place. The three most common types of fire extinguishers are air-pressurized water, carbon dioxide (CO 2), and dry chemical. 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. (d) False, increased concentration of carbon dioxide in air is believed to cause global warming. A good fuel should have high calorific value. True. Carbon Dioxide (CO2) Extinguishers. (5) 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. Class A, B and C . (vii) The friction of bamboos due to high wind velocity and rolling stones. Calorific value Answer. It occurs naturally in Earth's atmosphere as a trace gas.The current concentration is about 0.04% (412 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Add your answer and earn points. Wormald offers a range of portable fire extinguishers to suit all types and classes of fires. is called combustion. Overview: CO2 extinguishers are predominantly used for electrical fire risks and are usually the main fire extinguisher type provided in computer server rooms. Answer. NCERT Exemplar Class 8 Science Chapter 6 Combustion and Flame are part of NCERT Exemplar Class 8 Science. Write in brief about the reasons of forest fires. (c) kilojoule per gram (d) kilojoule per kilogram Question. True, air contains oxygen and oxygen is a supporter of combustion. (b) When the clothes of a person catch …………the person is covered with a…………… to extinguish fire. So, incorrect statement is option (c). 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. If yes, why? TRUE/FALSE. When the liquid carbon dioxide inside the extinguisher expands into a gas, the carbon dioxide pushes out any oxygen surrounding the fire. 17 Some words (underlined) in the following sentences are jumbled up. Answer. (b) Magnesium is a non-combustible metal. These can be fires where cooking liquids, oil, gasoline, kerosene, or paint have become ignited. Question. Dry Chemical. (4) Fire extinguishers discharged/partly discharged should be thrown away. (d) Calorific value of wood is higher than that of coal. 24 Match the following for the flame of a candle. (iv) The use of fires by villagers to ward off wild animals. 23. Carbon dioxide fire … 3. As the CO2 gas is expelled it turns into a cloud of dry ice, commonly referred to as "snow". Answer. Coal is also used in industries. Class B fires which involve flammable liquids and gases, solvents, oils, greases (excluding cooking oils/greases in depth) tars, oil-based paints and lacquers. Monthly inspections should be performed on fire extinguishers. The carbon dioxide extinguisher pushes oxygen away from the fire and replaces it with carbon dioxide, which is inflammable and more dense than air. Question. (c) Alcohol, CNG and LPG are inflammable substances. If you have vehicle which can run on petrol as well as CNG, which fuel will you prefer and why? (e) True B. (8) Fire Fighting Phases: Do not use water or halogenated hydrocarbons such as carbon tetrachloride. These are as follows: To obtain fuel wood, when trees are cut down, then all useful substances which can be obtained from trees are lost. 11 The calorific value of a fuel is expressed in a unit called It is because when CNG burns, it produces harmful products in very small amount. True or False 16. (i) Burning of wood produces a lot of smoke which causes respiratory diseases. (c) Kerosene (d) Hydrogen gas (g) The substances which vaporise during burning, give flame. Question. A "rest area" expansion chamber in a liquid flow line permits static electricity to bleed off. Indicate whether the following statements are True or False. According to the NFPA, some of the types of hazards and equipment that carbon dioxide systems protect are "flammable liquid materials; electrical hazards, such as transformers, switches, circuit breakers, rotating equipment, and electronic equipment; engines utilizing gasoline and … C02 being heavier than oxygen, covers the fire like a blanket. 6. Answer. CNG will be more economical. (d) low, inflammable Carbon dioxide is also very cold when it comes out of the extinguisher. Be thorough when using a CO 2 extinguisher. Fuel efficiency is determined by its calorific value which is the amount of heat energy produced on complete combustion of 1 kg of a fuel. (b) Wood, paper, CNG are ……………substances. Classes of Fire Definitions: Green = Suitable; Red = Not Suitable; Orange = Limited Fire happens when three things are in the same place at the same time: ... A foam extinguisher, on the other hand, works a bit more like a carbon dioxide extinguisher when the nozzle is open: the water and foaming solution swirl together in the nozzle, producing a much bigger volume of foam than the volume of the can itself. Down C02 being heavier than oxygen, covers the fire like a blanket. A fire protection system on most aircraft consists of a fire detection and a fire extinguishing system. Class B and C . Asked by Wiki User. Wiki User Answered . Question. Such a reaction is called explosion. (c) The………….. temperature at which a substance catches fire is called its…………..temperature. Which one of the following is a combustible substance? In such a condition what should Manu have done? Another way to prevent getting this page in the future is to use Privacy Pass. (d) Increased concentration of nitrogen in air is believed to cause global warming. Help her in this activity. The carbon dioxide (CO 2) extinguisher was invented (at least in the US) by the Walter Kidde Company in 1924 in response to Bell Telephone's request for an electrically non-conductive chemical for extinguishing the previously difficult-to-extinguish fires in telephone switchboards. Answer. (e) Greater the calorific value, better is the fuel. Carbon Dioxide Extinguishers . (c) Carbon dioxide is an excellent fire extinguisher. Ignition 5. Also write the false statements in their correct form. 3. Carbon Dioxide extinguishers are filled with non-flammable carbon dioxide gas under extreme pressure. The pressure in the cylinder is so great that when you use one of these extinguishers, bits of dry ice may shoot out the horn.
carbon dioxide is an excellent fire extinguisher true or false