Ask questions, doubts, problems and we will help you..
Ask questions which are clear, concise and easy to understand.
Ask Question
CBSE, JEE, NEET, CUET
Question Bank, Mock Tests, Exam Papers
NCERT Solutions, Sample Papers, Notes, Videos
Posted by Diksha Laniya🐥 5 years ago (10085318)
- 2 answers
Posted by Mohit Seervi 5 years ago (9688966)
- 1 answers
Posted by Omkar Bodas ? 5 years ago (10104534)
- 4 answers
Posted by Renu Bala 5 years ago (8548810)
- 2 answers
Lipi Nag 5 years ago (9680259)
Yogita Ingle 5 years ago (2577571)
Both oxygen and carbon dioxide have to be transported by the blood, therefore, the heart has different chambers to prevent the oxygen-rich blood from mixing with the blood-containing carbon dioxide. The carbon dioxide-rich blood has to reach the lungs for the carbon dioxide to be removed, and the oxygenated blood from the lungs has to be brought back to the heart. This oxygen-rich blood is then pumped to the rest of the body.
Oxygen-rich blood from the lungs comes to the thin-walled upper chamber of the heart on the left, the left atrium. The left atrium relaxes when it is collecting this blood. It then contracts, while the next chamber, the left ventricle, relaxes, so that the blood is transferred to it. When the muscular left ventricle contracts in its turn, the blood is pumped out to the body.
De-oxygenated blood comes from the body to the upper chamber on the right, the right atrium, as it relaxes. As the right atrium contracts, the corresponding lower chamber, the right ventricle, dilates. This transfers blood to the right ventricle, which in turn pumps it to the lungs for oxygenation.
Posted by Priyanka Meena 5 years ago (10158862)
- 5 answers
Vinay.K Kunde 5 years ago (9533179)
Posted by Prabhat Choudhary 5 years ago (10109677)
- 5 answers
Yogita Ingle 5 years ago (2577571)
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 (9551363)
- 1 answers
Yogita Ingle 5 years ago (2577571)
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 Nikhil Bhaskar 5 years ago (7536680)
- 1 answers
Yogita Ingle 5 years ago (2577571)
The village of Hosahalli has two very distinguished features.
The mango trees growing in the village of Hosahalli are extremely sour.
Even a bite from them can take the sourness straight to the brahmarandhra.
Secondly, the leaves of the creepers growing around the village are quite fascinating.
The leaves are huge enough to serve the afternoon meals without any further worry
Posted by Suraj Yadav 5 years ago (9596272)
- 4 answers
Rohit Rathore 5 years ago (10196736)
Posted by Ayush Gupta 5 years ago (10191016)
- 1 answers
Riya Rana 5 years ago (9993685)
Posted by Dev Dharam Singh 5 years ago (983513)
- 0 answers
Posted by ??? ?? 5 years ago (10184380)
- 3 answers
Posted by User Name 5 years ago (10191017)
- 1 answers
Posted by Bhawna Kushwah 5 years ago (9329151)
- 4 answers
Siddhi Deshattiwar 5 years ago (9151051)
Gaurav Seth 5 years ago (2898529)
Common Operating Machine Purposely Used for Technological and Educational Research.
Computer is not an acronym, it is a word derived from a word "compute" which means to calculate. So, in simple words you can say that computer is an electronic device which is used for fast calculation.
Some people say that COMPUTER stands for Common Operating Machine Purposely Used for Technological and Educational Research.
Posted by Kanav Grover Vi C Grover 5 years ago (10130135)
- 3 answers
Kanav Grover Vi C Grover 4 years, 10 months ago (10130135)
Posted by Kavya Sehrawat 5 years ago (9551363)
- 4 answers
Gaurav Seth 5 years ago (2898529)
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 (10161628)
Prem Mishra 5 years ago (10161628)
Prem Mishra 5 years ago (10161628)
Posted by Ramlal Soren 4 years, 10 months ago (10008732)
- 0 answers
Posted by Kavya Sehrawat 5 years ago (9551363)
- 4 answers
Aasma Singla 5 years ago (9054255)
Prem Mishra 5 years ago (10161628)
Gaurav Seth 5 years ago (2898529)
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 (2898529)
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 Arsh Singh 4 years, 7 months ago (10173841)
- 1 answers
Gaurav Seth 4 years, 7 months ago (2898529)
Write a letter to Delhi Sports, Daryaganj, New Delhi, placing an order for sports articles like footballs, cricket balls, Tennis balls and cricket bats to be supplied to your school. Sign as Ravi/Raveena, Sports Secretary.
Answer:
Happy Time Public School
Bhajan pura
New Delhi 1100XX
19 January 20XX
The Manager
Delhi Sports, Darya Ganj
New Delhi 1100XX
Dear Sir
Subject: Placement of sports goods
This has reference to the quotation dated 19 December 20XX. Kindly send the following items at the above address.
| Name of the Items | No. of Items | Remarks |
| Football | 10 | Sparton |
| Cricket balls | 10 | Leather |
| Tennis balls | 20 | Vicky (brand) |
| Cricket bats | 10 | SS |
All the items should be in good condition, well bound and packed properly and delivered within a week. The payment will be made by cash once the items reach us. Any damage during transportation would be your responsibility. Though in the past, you have never given us any opportunity to complain and – the goods have always reached us well on time, and in excellent condition as per our specifications, we do expect the same delivery this time as well.
Yours faithfully
Raveena
(Secretary)
Posted by Chhavi Choudhary 5 years ago (9337196)
- 1 answers
Gaurav Seth 5 years ago (2898529)
Chocs Ahoy.
Cheeky Chocolates.
Sugar and Smiles.
Terrific Treats.
Milky Goodness.
Chunks of Heaven.
My Chocolate Life.
Bars of Bliss
choco Decker
Tirppy Terk
Duo bar
Ever -Chocolate & more.
Orre lick
white wrapper
Angelbar
Zipkid
Square pix
surfberry
Crunch Creation
Supreme Surf
GlueBite
walt wrapper
Posted by Md Shadab 5 years ago (4856198)
- 2 answers
Tiger$ Praful Jawale 5 years ago (9390811)
Gaurav Seth 5 years ago (2898529)
(a) In the upper layers of the atmosphere, a layer of ozone is formed, which gets depleted due to chloro fluoro carbons and creates a hole called ozone hole.
(b) Ozone hole is found above Antartica, over the North pole.
(c) UV radiation will reach the earth and cause diseases like - cancer, reduce immunity and reduce crop yield.
The ozone layer present in the stratosphere acts as a protective shield. It saves the earth from the harmful ultraviolet rays of the sun. The compounds containing CFCs (chlorofluorocarbons) are mainly responsible for ozone layer depletion as these compounds react with ozone in the presence of ultraviolet rays to form oxygen molecule and thus, destroying ozone.
Posted by Md Shadab 5 years ago (4856198)
- 1 answers
Gaurav Seth 5 years ago (2898529)
The harmful effects of UV radiations are as mentioned below
1. causes skin cancer
2. cause sun burn
3. damage immune system
4. damage eyes
5. ages skin
6. weakens plastics
Posted by Md Shadab 5 years ago (4856198)
- 1 answers
Gaurav Seth 5 years ago (2898529)
- Ozone is a molecule of oxygen with three atoms of oxygen, O3.
- It covers the Earth’s atmosphere and is present in the stratosphere. It does not allow the harmful ultra-violet radiations coming from the sun to reach our Earth surface.
- These ultra-violet radiations cause ionising effect, can cause cancer and genetic disorder in any life-forms.
- The ozone is getting depleted at the south pole near Antartica. The ozone depletion is due to the halogens like CFC (chlorofluorocarbon) released in the air.
- Chlorine and fluorine reacts with the ozone and splits it, thereby leading to formation of a big hole called ozone hole.
- Thus, we need to protect the ozone layer from getting depleted by reducing the consumption of fossil-fuels and other factors which leads to the depletion of ozone layer.
Posted by Md Shadab 5 years ago (4856198)
- 1 answers
Gaurav Seth 5 years ago (2898529)
The thinning of ozone layer allows more ultra violet (UV) radiations to pass through it which then strike the earth. These cause following harmful effects on man, animals and plants:
(i) Skin cancer.
(ii) Damage to eyes, also increase incidence of cataract disease in eyes.
(iii) Damage to immune system.
(iv) Increased embryonic mortality in animals and humans.
(v) In plants too, there will be increased death rate of seedlings, increased incidence of harmful mutations and reduction in yields.
Posted by Md Shadab 5 years ago (4856198)
- 3 answers
Suraj Yadav 5 years ago (9596272)
Gaurav Seth 5 years ago (2898529)
Oxygen molecule splits into atomic oxygen (O) at higher levels of an atmosphere because of higher energy of UV radiations.
So, O2⟶O+O
O2+O⟶O3 (Ozone)
Damage to the ozone layer is a cause of concern to us as it forms a layer in the atmosphere which protects us from the harmful UV radiation.
Damage to ozone layer can cause penetration of UV rays in the earth surface which damages human organs, plants, etc.
Posted by ??? ?? 5 years ago (10153843)
- 3 answers
Gaurav Seth 5 years ago (2898529)
Rhyme Scheme: The whole poem follows ABAAB rhyme scheme.
Metaphor - The whole poem is an extended metaphor and the road acts as a metaphor for life.
Alliteration - “wanted wear”
Personification - The fork in the woods refers to the life decisions one has to make.
Repetition - “Somewhere ages and ages hence”
Consonance and assonance - “And that has made all the difference.” “Yet knowing how way leads on to way”
Posted by Zoofeen Farooqui 5 years ago (10190820)
- 4 answers
Posted by Annaniya Chauhan 5 years ago (10098972)
- 2 answers
Annaniya Chauhan 5 years ago (10098972)
Posted by Parmeshwari Vaghela 5 years ago (10190746)
- 1 answers
Posted by Aditya Yadav 5 years ago (8743581)
- 0 answers
myCBSEguide
Trusted by 1 Crore+ Students
Test Generator
Create papers online. It's FREE.
CUET Mock Tests
75,000+ questions to practice only on myCBSEguide app
Adnan Gaming 5 years ago (10205714)
1 Thank You