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Ask QuestionPosted by Poonam Sharma 5 years ago
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Posted by Yash Rathee 5 years ago
- 3 answers
Gaurav Seth 5 years ago
Comment vous appelez-vous ? - What's your name?
Extra:
- Bonjour ! - Hello! (formal)
- Salut ! - Hello! (informal)
- Je m’appelle Paul. - I'm called Paul.
- D’où venez vous ? - Where do you come from?
- Je viens des Etats-Unis. - I come from the United States.
- Vous parlez bien français. - You speak French well.
- Juste un petit peu. - Just a little bit.
Posted by Sahil K 5 years ago
- 2 answers
Jyoti Tiwari 5 years ago
Posted by Kunal Ff 5 years ago
- 2 answers
Yogita Ingle 5 years ago
The process of releasing energy from food is called respiration. The process of respiration involves taking in oxygen (of air) into the cells, using it for releasing food, and then eliminating the waste products (carbon dioxide and water) from the body.
Posted by Siraj Chaudhary 5 years ago
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Posted by Siraj Chaudhary 5 years ago
- 1 answers
Posted by Siraj Chaudhary 5 years ago
- 3 answers
Thejasvini S. V 5 years ago
Aakash Gupta 5 years ago
Gaurav Seth 5 years ago
All the physical parts of a computer that can be touched, seen and felt are called hardware.
Computer hardware includes the physical parts of a computer, such as the case, central processing unit (CPU), monitor, mouse, keyboard, computer data storage, graphics card, sound card, speakers and motherboard.
Posted by Saksham Kumar 5 years ago
- 4 answers
Posted by Saksham Kumar 5 years ago
- 2 answers
Kashish ☺️✌️ 5 years ago
Yogita Ingle 5 years ago
A concave mirror has the reflecting surface that caves inwards. Concave mirrors converge light to one prime focus point. Therefore, they are also called converging mirrors. They are used to focus light.
Concave Mirror
- A concave mirror produces a smaller, bigger and inverted image based on its distance from the object.
- When the distance between object and mirror is large, a small inverted virtual image is formed.
- As the object is brought closer, the image becomes larger.
- At a very close distance, the image is large and upright.
Posted by Pradumn Janghela 5 years ago
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Posted by S.Harishkumar 7C 5 years ago
- 3 answers
Debangi Ghosh Debangi Ghosh 5 years ago
Posted by Khushi Rathee 5 years ago
- 1 answers
Posted by Dhanista Nongmeikapam 5 years ago
- 3 answers
Posted by Radhika Garg 5 years ago
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Posted by Prabhat Choudhary 5 years ago
- 5 answers
Yogita Ingle 5 years ago
Simple interest is the interest paid only on the original amount of money(Principal).The amount of interest is given by I = Prt, where P is the principal, r is the annual interest rate in decimal form, and t is the loan period expressed in years.
Posted by Kavya Sehrawat 5 years ago
- 1 answers
Yogita Ingle 5 years ago
The process of deriving large crystals of pure substances from their solutions is known as crystallisation. It is a physical change. Crystals of salt are obtained by the evaporation of sea water.
Similarly crystals of copper sulphate can be obtained by adding copper sulphate powder to the boiling solution of water and dilute sulphuric acid. This mixture when filtered and allowed to cool produces crystals of copper sulphate.
Posted by Kavya Sehrawat 5 years ago
- 4 answers
Gaurav Seth 5 years ago
1. When a candle burns, both physical & chemical changes occur. On heating, candle wax melts and form liquid wax. It is a physical change. Since it again turns into solid wax on cooling. This is a reversible change. When a candle is burnt in air, the mass of the product is increased due to atmospheric oxygen which show a that it is a chemical change.
3.
Rusting of Iron
When an iron object is left in damp air (or water) for a considerable time, it gets covered with a red-brown flaky substance called rust. This is called rusting of iron. During the rusting of iron, iron metal combines with the oxygen (of air) in the presence of water (moisture) to form a compound iron oxide. This iron oxide is rust.
Iron + Oxygen +Water ——> Iron Oxide
Fe + O2 + H2O ——> Fe2O3
Rust is iron oxide (Fe2O3). Thus, rust and iron are not the same substance. Rusting of iron is a chemical change.
Methods of preventing iron from rusting
(1) Rusting of iron can be prevented by galvanisation
The process of depositing a thin layer (or coating) of zinc metal on iron objects is called galvanisation.
Galvanisation is done by dipping an iron object in molten zinc metal. A thin layer of zinc metal formed on the surface of an iron object protects it from rusting (because zinc metal remains unaffected by air and moisture). The iron sheets used for making buckets, drums, dust-bins and sheds (roofs) are galvanised to prevent their rusting. The iron pipes used in our homes to carry water are also galvanised to prevent rusting.
(2) Iron is coated with chromium to prevent rusting
This is called chrome-plating. Chromium metal is resistant to the action of air and moisture. So, when a layer of chromium is deposited on an iron object, then the iron object is protected from rusting.
Chromium-plating is done on steel furniture, taps, bicycle handle bars and car bumpers, etc, made of iron and steel to prevent them from rusting.
Prem Mishra 5 years ago
Prem Mishra 5 years ago
Prem Mishra 5 years ago
Posted by Kavya Sehrawat 5 years ago
- 4 answers
Aasma Singla 5 years ago
Prem Mishra 5 years ago
Gaurav Seth 5 years ago
2.
(1) Rusting of iron can be prevented by painting
When a coat of paint is applied to the surface of an iron object, then air and moisture cannot come in contact with the iron object and hence no rusting takes place. The window grills, railings, steel furniture, iron bridges, railway coaches, and bodies of cars, buses and trucks, are all painted regularly to protect them from rusting.
(2) Rusting of iron can be prevented by applying grease or oil
When some grease or oil is applied to the surface of an iron object, then air and moisture cannot come in contact with it and hence rusting is prevented.
The tools and machine parts made of iron and steel are smeared with grease or oil to prevent their rusting.
(3) Rusting of iron can be prevented by galvanisation
The process of depositing a thin layer (or coating) of zinc metal on iron objects is called galvanisation.
Gaurav Seth 5 years ago
1.
Examples of chemical changes :
Souring of milk
Formation of curd from milk
Cooking of food (like rice and chapatis)
Spoilage of food
Change in colour of cut apple (cut brinjal or cut potato) on keeping in air
Photosynthesis
Digestion of food
Neutralisation reaction
Explosion of a firework (or cracker)
Burning of magnesium ribbon
Burning of fuels (like burning of wood, coal, kerosene, LPG and biogas)
Burning of dry leaves
Burning of candle wax
Burning of incense stick
Rusting of iron
Ripening of fruits
Posted by Paridhi Jain Jain 5 years ago
- 3 answers
Akshit Kamal 5 years ago
Posted by Vikas H 5 years ago
- 5 answers
Prateek Kumar 5 years ago
Gaurav Seth 5 years ago
Humans are unable to digest cellulose because the appropriate enzymes to breakdown the beta acetal linkages are lacking. ... They have the required enzymes for the breakdown or hydrolysis of the cellulose; the animals do not, not even termites, have the correct enzymes. No vertebrate can digest cellulose directly.
Posted by Utkarsh Kumar 5 years ago
- 1 answers
Gaurav Seth 5 years ago
1. Agriculture has changed life of human beings drasticaly. Early men used to live nomadic life, they were hunter-gatherers but after the development of agriculture or farming, humans started forming settlements.
2. In these settlements, people began farming, building permanent shelters like mud houses or thatched houses, making better tools and clothing.
3. The surplus production of food grains helped humans to concentrate on other activities like trade and commerce,craftsmanship,teaching,builders and administration etc.
4. They also found important uses of animals. They started taming or domesticating sheep, dogs, goats, and cow etc. They used the animals for various purposes like to carry heavy burdens over long distances,for wool,milk and security purposes etc.
5. Each of these changes made humans life more stable and comfortable.They started evolving into more civilised and advanced humans.
Posted by Amneet Ersheen 5 years ago
- 4 answers
Gaurav Seth 5 years ago
The air in the atmosphere is mixture of many Gases
The air around us is a mixture of gases, mainly nitrogen and oxygen, air also contains very smaller amounts of water vapor, argon, and carbon dioxide, and very small amounts of other gases, suspended dust, spores, and bacteria.
Posted by Jayasish Nath 5 years ago
- 1 answers
Gaurav Seth 5 years ago
15.5% of Rs 3000 =
3000 x 15.5
100
= 465
Therefore, 15.5% of Rs 3000 = Rs 465
Posted by Waishnu Gani 5 years ago
- 1 answers
Posted by Sakshi Singh 5 years ago
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Posted by Mahimamayee Senapati 5 years ago
- 2 answers
Aasma Singla 5 years ago
Gaurav Seth 5 years ago
All animals require food for obtaining energy, growth, repair of damaged parts and functioning of the body. The process of taking food by an animal and its utilisation in the body is called animal nutrition.
Posted by Aditi Patil 5 years ago
- 3 answers
Gaurav Seth 5 years ago
Nishad turned sympathetic towards Mr Nath seeing his gaunt appearance. His attitude changed further when he came to know that he used to give regular tips to Ramesh for bringing his food. Then he also remembered his mother's words that Mr Nath was a polite man.
Posted by Avni ? 5 years ago
- 5 answers
Posted by Divyanshi Pathak 5 years ago
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Posted by Mannatpreet Kaur 5 years ago
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