अमानक वर्ण

अमानक वर्ण  Hindi grammar questions for competitive exam part-5




1  शुद्ध वर्तनी    2 . अमानक वर्ण 

 (i)  -शुद्ध वर्तनी ➨ बर्तन की शुद्ध " वर्तनी " क्या है ?
बर्तन का शुद्ध वर्तनी ➨ "बर्तन " का शुद्ध वर्तनी   "बरतन "है ∣

  (ii) . अमानक वर्ण - हिंदी में बहुत से ऐसे वर्ण हुआ करते थे ,जो की वर्तमान समय में चलन में नहीं है ,अथवा हिंदी के मूल वर्णो में शामिल नहीं है।  इस प्रकार के  सभी वर्ण " अमानक वर्णो " की श्रेणी में  आते हैं Ι
 अर्थात वे   " वर्ण " जो पूर्व में तो मान्य रहे हो ,परन्तु वर्तमान वर्णमाला के दृस्टीकोण   से मान्य न  होते हो , अमानक वर्ण है ।
अमानक वर्ण क्या है ➨ ऐसे वर्ण जिनका कोई " मानक " न हो , तथा जो सर्वमान्य न हो " अमानक " वर्ण है , अथवा ऐसे वर्ण जिनका पहले तो मानक रहा हो परन्तु वर्तमान समय में उनका कोई " मानक " न  हो अमानक वर्ण कहलाते है ।

अमानक वर्ण किसे  कहते है ➨ जब कोई वर्ण वर्तमान परिपेक्ष्य  के मानकों  पर खरा नहीं उतरता अथवा वर्तमान में स्वीकार वर्णमाला में शामिल न  हो , अथवा पूर्व में स्वी…

Combustion and fossil fuel

Combustion and fossil fuel 

Combustion and fossil fuel

Combustion and fossil fuel 


 Science in everyday life for class 8 Science Chapter 5

HELLO friends, science in everyday life for class 8 science chapter 5 Combustion and fossil fuel are provide here with simple step by step explanations. In this atical, all the questions and answers of science in everyday life for class 8 science chapter 5 Combustion and fossil fuel are given. Which will be useful for your study




1- combustion- the process of burning of a a substance in the the presence of air or oxygen with the the liberation heat and light is called conception. 


2- combustion substance- substances that burn in air or oxygen to produce heat and light are called combustion substances. 


3- known combustible substances- substances that do not burn in air or oxygen to produce heat and light are called non-combustion substances. 


4- ignition temperature- the temperature at which a particular substance burn in the presence of air is called its ignition temperature. 


5- fuels- substances that produce heat and light energy on burning are called fuels. 



Question-1- what is combustion? 


Answer- the process of burning of a substance in the presence off air air or oxygen with the liberation of heat and light is called combustion. 




Question-2- different between combustion and non-combustion substance, give two example of each? 



Answer- 
1-combustion 

*Substance that burn in air or oxygen to produce heat and light are called combustion substance. 

2-Non-combustion 

* that do not burn in air or oxygen to produce heat and light are called non-combustion substance. 

Question-3- difference between complete combustion and incomplete combustion? 


Answer- 1- complete combustion 


* this type of combustion takes place in in inadequate amount of air or oxygen. It results in the the formation of carbon dioxide, water ,heat and light. 


2-Incomplete combustion - this type of combustion of takes place in in inadequate amount of air or oxygen. It result in the formation of carbon monoxide, soot, water ,heat and light .



Question-4- state the three necessary conditions for combustion? 


Answer- the following condition are necessary for combustion to take place. 


* presence of a combustion a substance. 


* presence of a a supporter of combustion. 


* attainment of ignition temperature. 



Question-5- what is ignition temperature? Why are substances like alcohol and petrol called inflammable substances. 


Answer- the temperature at which a particular substance burns in the presence of air is called ignition temperature. Substances such as alcohol, petrol, LPG, and nylon. Fibre catch fire very easily. This is because these substances have low ignition temperature. Such substances are called inflammable substances. 




Science in everyday life for class 8 Science in everyday life
Science in everyday life for class 8 Science in everyday life

Question-6- describe the the two common type of Fire extinguishers? 


Answer- two common type of Fire extinguishers are carbon dioxide fire extinguisher and Soda acid fire extinguishers. 


*Carbon dioxide fire extinguishers- this type of fire extinguisher has a concentrated solution of sodium extinguisher has concentrated solution of sodium hydrogen carbonate and Sulphuric acid in separate compartment. When the fire extinguisher is used, the the two substances come into contact with each other, producing carbon dioxide. 



Question7- different between luminous and non- luminous flame? 


Answer-A yellow flame is also called luminous flame, as it emits a lot of light.a luminous flame is is generally observe when there is is insufficient oxygen. Its temperature is lower than that of a blue flame and it leaves behind black soot and other reduce. A blue image also called are non- luminous flame as it it emits very little light. A  blue flame is generally observed when there is is adequate amount of oxygen available. This type of flame leaves behind no reduce. 




Question-8- what is a fuel? Give two example each of solid, liquid, and gases fuel? 



Answer- substance that produce heat and light energy on behind are called fuels. 

* solid fuels- coal,wood. 

* liquid fuel- petrol, kerosene 

* gas fuel- C.N.G,LPG. 




Question-9- why are methane and LPG CONSIDERED idle for use as domestic fuels? 



Answer- conservation of fossil fuel can be done by... 

* judicious use of the the existing resource. 

* use of alternate source of of energy like tidal power, wind energy, solar energy and nuclear energy to meet our fuel and energy needs. 


Question-10- different between exhaustible and inexhaustible natural resource. Give two example of each? 



Answer- 
1-inexhaustible natural resource- these are the source of which there is a limitless supply sunlight and air are examples of inexhaustible resources. 

2-Exhaustible natural resource- there are resource whose supply is limited. Their overuse solid, therefore be avoided. Fossil fuel, forest and wildlife are example of Exhaustible resources. 


Science in everyday life for class 8 Science Chapter 5 Combustion And Fossil Fuels

Science in everyday life for class 8 Science Chapter 5 Combustion And Fossil Fuels


Question 11- explain the different zone of a candle flame? 


Answer- there are three zones of candle flame- 


1- the middle zone(yellow)- is less hot the the outer zone. Hair incomplete combustion of wax vapours (due to low oxygen) produce carbon particles(which glow, giving the zone its yellow colour) and carbon monoxide. This June emits the most light. 


2- the outer zone(blue)- if the hottest part of the flame. In the zone, the wax vapours I have enough oxygen to burn completely(producing carbon dioxide and water). Which zone emits very little light. 


3- the inner zone(black)- is the coolest part of the flame. In this zone, the the wax vapours remain unburned as no oxygen is available. Did John is completely dark and emits no light. 



Question 12- what are fossil fuel? How were coal and petroleum formed? 


Answers- fossil fuels are formed from the the bu buried remains of plants and animals over a period of millions of years. Coal petroleum and natural gas are example of fossil fuel. 



Question.-13- name any four yeah air pollutants and describe their harmful effects? 


Answer- some of the main air air pollutant and their harmful effects are given below:- 




* carbon monoxide is a colourless, odorless who, and tasteless gas. It is produced by incomplete conbustion of fossil fuel. Exposure two carbon monoxide can cause headache and dizziness and can even lead to coma and death. 




* carbon dioxide- this can lead to an increase in the the Global average temperature. This phenomena is called global warming. Can cause this melting of polar ice caps and Glacier, resulting in a rise in in sea level . 




* the oxides of of Sulphur and nitrogen- this gases react with oxygen and water vapour present in the air to produce dilute solution of sulfuric acid and nitric acid, which fall on earth at acid rain and damage plants, aquatic life, soil and buildings. 



*soot particles- these particles can enter our bodies when we breathe and trigger asthma attacks and cause wheezing, coughing and respiratory irrigation.

questions-14-what are the products obtained on refining petroleum?write their main uses?

answer- 
Science in everyday life for Science in everyday life class 8 Science

Science in everyday life for Science in everyday life class 8 Science


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class 8 science question and answer CBSC/NCERT

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