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Earth’s atmosphere is a mixture of nitrogen (79%), oxygen (20%), and a small fraction of carbon dioxide, water vapours and other gases. This makes the existence of life possible on Earth. However, the atmospheres on Venus and Mars mainly consist of carbon dioxide. The amount of carbon dioxide on these planets can range from 95% to 97%.

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Why iron reacts with steam instead of water

Posted by Ajay ???? 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 8 months ago

An equation for the reaction of: a) iron with steam

When a metal reacts with steam then the products formed are metal oxide and hydrogen gas.
Metal + steam --------> Metal oxide + Hydrogen

When red hot iron reacts with steam to form iron(II,III) oxide and hydrogen.

3Fe(s) + 4H₂O(g) steam -------> Fe₃O₄ (s) + 4H₂(g)

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If an atom contains one electron and one proton will it carry any charge or not

Posted by Eswari Lalitha 5 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Nikita Roster 5 years, 8 months ago

It will not carry any type of charges

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Kashish Chettri 5 years, 8 months ago

No , it will not carry any charges

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SI Unit of kg ?

Posted by Rajiv Singh 5 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Mansi Class12 5 years, 8 months ago

Question is wrong because there is no unit of kg. Kg is the unit of mass

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Neha Pandey 5 years, 8 months ago

This question is invalid

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In a football and a stone of the same size, the inertia of A. Football is greater B. Football is lesser C. Stone is greater D. Stone is lesser

Posted by Kashika Chowdary 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Meghna Thapar 5 years, 7 months ago

As the mass of an object is a measure of its inertia, objects with more mass have more inertia. Hence, inertia of stone is greater than the inertia of football because mass of stone is higher than the mass of football even both are of same size

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Why is it more painful to jump on a concrete floor than to jump in a water surface?

Posted by Kritika Dhiman 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 8 months ago

1 .If a man falls on a soft landing site like heap of sand, the man takes
a longer time to come to stop.
2. The rate of change of momentum is less due to which a smaller stopping force acts on the man and he does not get hurt.
Thus, Sand ,being soft reduces,the man's monentum more gently.

3. If the man lands on hard ground like cement floor, then his momentum will be reduced to zero in,very short time .
4. The rate of change of momentum will be large due to,which a large opposing force,will act on the man.
5. This force,can lead to serious injuries to the man.

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Is golgi apparatus is involved in the formation of lysosomes

Posted by Ajul Thara 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 8 months ago

Along with the function of secretion of various enzyme proteins and producing vacoules, Golgi apparatus is also involved in the synthesis of cell wall, plasma membrane and lysosome.

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What is force of gravity

Posted by Hariprasad Pillai 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 8 months ago

A force that attracts a body towards the centre of the earth, or towards any other physical body having mass.

Issac Newton defined the force of gravity as follows:

“Every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them.”

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What is genatic manmanipulation

Posted by Sandeep Dube 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 8 months ago

Genetic manipulation is a process in which genes of desirable characters are taken from a plant and transferred to another plant by the technique of hybridisation. Genetic manipulation helps in obtaining desirable agronomic characters liked Dwarfness in cereals and tallness and profuse branching in fodder crops. It is useful in developing varieties with higher yield, good quality, biotic and abiotic resistance, short maturity period, wider adoptability and desirable agronomic characteristics.

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What do you mean by oxygen cycle

Posted by Karan Bungla 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Yogita Ingle 5 years, 8 months ago

Oxygen is an important component of everyday life. We cannot survive without oxygen. It comprises about 21% of atmospheric air. It is a component of several biological molecules such as carbohydrates, proteins, nucleic acids, and fats.

Like carbon dioxide, oxygen too is cycled through the process of photosynthesis and respiration. Oxygen is also utilized during combustion or burning.

Steps of oxygen cycle.

Step 1)Animals take in oxygen through the process of respiration. And release CO_{2 }into the atmosphere.

Step 2)Carbon dioxide, released by animals is used in plants in the process of photosynthesis.

Step 3)Plants release oxygen into the atmosphere as a by-product of photosynthesis.

step 4)Fuels need oxygen for combustion so they take oxygen and release CO_{2 }into the atmosphere as a by product along with other gases like N_{2 }etc.

Step5)CO_{2 }is released into the air in the process of decaying of dead animals and plants.

step 6)This CO_{2} is taken by plants for the process of photosynthesis and O_{2} is released, and this process continues.

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Why mitochondria is known as the power house of the cell

Posted by Tuke Yark 5 years, 8 months ago

CBSE > Class 09 > Science

3 answers

Nikita Roster 5 years, 8 months ago

Becos it contains energy

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Ritik Pulani 5 years, 8 months ago

Because it supply energy to other organelles in the form of ATP(adenosine triphosphate)

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Rohit Singh 5 years, 8 months ago

Because it comtains energy

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What is si unit of temperature

Posted by Anil Kumar 5 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Tina ? 5 years, 7 months ago

Kelvin

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Abhay Thakur 5 years, 8 months ago

Kelvin

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Arshad Rasheed 5 years, 8 months ago

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Vansh Bhatia 5 years, 8 months ago

Kelvin

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Anshak . 5 years, 8 months ago

Kelvin

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Jj thomson,s mdel of atom

Posted by Anmol Xyz 5 years, 8 months ago

CBSE > Class 09 > Science

1 answers

Dhruv Raj 5 years, 8 months ago

In Thomson's model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged “plums” surrounded by positively charged “pudding”. The 1904 Thomson model was disproved by Hans Geiger's and Ernest Marsden's 1909 gold foil experiment

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Law of conservation of energy derive formulas

Posted by Anmol Kushwaha 5 years, 8 months ago

CBSE > Class 09 > Science

5 answers

Yuvika Mourya 5 years, 8 months ago

By these all equation we got the conclusion energy can't be created nor destroyed

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Yuvika Mourya 5 years, 8 months ago

Please reply whether you understood or not?

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Yuvika Mourya 5 years, 8 months ago

Now at last but not least, ?the body is at bottom of the cliff so the PE is 0 becoz his final v is 0. KE is1/2mv^2 now again take equation of v^2-u^2= 2gh here we have took h becoz he had covered hieght of cliff. Therefore again equation is v^2=2gh now keep it on KE equation therefore it is mgh. Mechanical energy is KE+PE. which = to mgh

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Yuvika Mourya 5 years, 8 months ago

Now, at the middle of the hieght of the cliff at B point when he travel distance s. PE will be mg(h-s) therefore it is mgh - mgs and KE is 1/2mv^2 <- this we all know but v^2-u^2=2gs here we will take s not h because body have not covered whole hieght yet. Therefore as u=0, equation will v^2 = 2gs now keep this value v^2 in kinetic energy's formula so it will be = to (1/2m)into(2gs) so according to this statement KE is mgs. Therefore machenical energy is KE +PE that is mgs +mgh-mgs =mgh.

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Yuvika Mourya 5 years, 8 months ago

At top of the cliff if body is standing let it be 'A'. Then Ke will be 0 because the body is at rest so v=0 therefore ->If KE =1/2 mv^2 then KE will be 0. and potential energy will be muh. Therefore machenical energy = KE +potential energy that is mgh

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What do you mean by mitrochondria

Posted by Mukul Mittal 5 years, 8 months ago

CBSE > Class 09 > Science

2 answers

Abhinav Mishra 5 years, 8 months ago

Mitracondria is the most important cell organells and it is also called as power house the cell it takes O2 and glucose to produce co2 and H2o and ATP (adanosine triphosphate)

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Mukul Mittal 5 years, 8 months ago

It is the powerhouse of the cell it convert our food into the seo2 and O2 and provide energy the energy is used in our cellular activities like respiration etc.

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Z is equal to 3 what is the valency of the element

Posted by Nakshatra Sharma 5 years, 8 months ago

CBSE > Class 09 > Science