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The ability of the human eye to adjust itself such that it can see objects which are nearby and faraway is called Accommodation.
It primarily involves the lens and ciliary muscles.
The ciliary muscles are capable of modifying the curvature of the lens and thereby affecting the focal length of the lens.
When viewing objects which are nearby, the ciliary muscles contract, the lens becomes thicker. It is squeezed into a more convex shape and the focal length decreases (curvature increases). The images again falls on the retina. Note that here the eye is 'accommodating' by taking a thicker shape so that the image falls on the retina.

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Name the ore of Mercury. With the help of balance chemical equation , explain the process of extraction of Mercury from it ore.

Posted by Puspendra Rajawat 6 years, 4 months ago

CBSE > Class 10 > Science

2 answers

Gaurav Seth 6 years, 4 months ago

The answer is Cinnabar.

Explanation:

The ore of mercury is cinnabar. Its formula is HgS and is called mercury(ii) sulfide.

Mercury ore is obtained through the extraction process. Following steps are involved in the process

Step 1- In first step, ore is roasted.

2HgS + 3 o2 -----> 2HgO+ 2 SO2

Step 2- In this step, the mercury oxide is heated strongly at a 300-celsius temperature. Mercury oxide decomposes at this temperature and pure mercury metal is obtained.

2HgO+ heat ------> 2Hg + o2

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Puspendra Rajawat 6 years, 4 months ago

Do hrydhv rh dgcr tsb du

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From where I will take oxygen in night time

Posted by Deepanshu Garkoti 6 years, 4 months ago

CBSE > Class 10 > Science

2 answers

Deepanshu Garkoti 6 years, 4 months ago

Pagal ho Gaya hai Kya common sense nahi hai

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Arush Yadav 6 years, 4 months ago

In nose

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50 assertion reason type questions

Posted by Shivam Srivastav 6 years, 4 months ago

CBSE > Class 10 > Science

0 answers

ANSWER

Explain cleaning action of soap

Posted by Beauty... ??? 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Gaurav Seth 6 years, 4 months ago

Cleansing action of soaps:
The dirt present on clothes is organic in nature and insoluble in water. Therefore, it cannot be removed by only washing with water. When soap is dissolved in water, its hydrophobic ends attach themselves to the dirt and remove it from the cloth. Then, the molecules of soap arrange themselves in micelle formation and trap the dirt at the centre of the cluster. These micelles remain suspended in the water. Hence, the dust particles are easily rinsed away by water.

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How will you dinstinguish alcohol and carboxylic acid chemically

Posted by Beauty... ??? 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Gaurav Seth 6 years, 4 months ago

Alcohols and carboxylic acids can be distinguished by litmus test and Reaction with sodium hydrogen carbonate

(i)Litmus test – Alcohol will have no effect on the litmus paper. Carboxylic acid acid will change blue litmus paper into red.

(ii)Reaction with sodium hydrogen carbonate – Alcohol has no reaction with sodium hydrogen carbonate (NaHCO3) but in the case of Carboxylic acid it reacts with NaHCO3 which gives CH3COONa, CO2 and H2O. The reaction is evident as the carbon dioxide will turn the lime water milky.

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How will you distinguish alcohol and carboxylic oil and butter

Posted by Beauty... ??? 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 6 years, 4 months ago

We can distinguish between an alcohol and a carboxylic acid on the basis of their reaction with carbonates and hydrogen carbonates. Acid reacts with carbonate and hydrogen carbonate to evolve CO₂ gas that turns lime water milky.

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What do you mean by analogous organ.

Posted by Muskan??? Pandey 6 years, 4 months ago

CBSE > Class 10 > Science

2 answers

Yogita Ingle 6 years, 4 months ago

Analogous organs are those organs which have the different basic structural design and origin but have similar functions.For example: The wings of birds and insects.

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Sharanu Ghante 6 years, 4 months ago

They have different basic structure and origin but have similar apperence and perform similar functions

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Ch-9 ki hindi bhej do plzz.(shamushi)

Posted by Sachin Mishra 6 years, 4 months ago

CBSE > Class 10 > Science

0 answers

ANSWER

What is rain water harvesting?

Posted by Ansh Namdev 6 years, 4 months ago

CBSE > Class 10 > Science

3 answers

Asmilo Hall 6 years, 4 months ago

My pleasure Ansh Bro!?

2Thank You

Ansh Namdev 6 years, 4 months ago

Thnx sis

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Asmilo Hall 6 years, 4 months ago

Rain water harvesting is a technique of collection and storage of rainwater into natural reservoirs or tanks, or the infiltration of surface water into subsurface aquifers (before it is lost as surface runoff). One method of rainwater harvesting is rooftop harvesting.

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Can any one explain me the structure of human eye

Posted by Apoorva ..... 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Asmilo Hall 6 years, 4 months ago

The eye is made up of three coats, or layers, enclosing various anatomical structures. The outermost layer, known as the fibrous tunic, is composed of the cornea and sclera. The middle layer, known as the vascular tunic or uvea, consists of the choroid, ciliary body, pigmented epithelium and iris.

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Define superior and inferior venacava

Posted by S S 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Yashi .... 6 years, 4 months ago

The inferior carries deoxygenated blood from the lower half of the body to the right atrium of the heart. The corresponding vein which is superior vena cava carries deoxygenated blood from the upper half of the body.

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Why ethene discolourised the bromine water but ethane do not?

Posted by Simpal Kumar 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Yashi .... 6 years, 4 months ago

As we know that ethene has double bond and so is unsaturated.It reacts with bromine to give colourless compound but ethane is a saturated hydrocarbon. Hence, it does not decolourise bromine water.

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Deep online ao to reply ker dena

Posted by Shivam Mishra 6 years, 4 months ago

CBSE > Class 10 > Science

8 answers

Jacquilene? Fernandez 6 years, 4 months ago

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Shivam Mishra 6 years, 4 months ago

hii deep what happen

1Thank You

Jacquilene? Fernandez 6 years, 4 months ago

Bolo??? Aap kon ??

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Apoorva ..... 6 years, 4 months ago

Honey ji kaha gayi

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Apoorva ..... 6 years, 4 months ago

Hi deep

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Apoorva ..... 6 years, 4 months ago

Shivam

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Apoorva ..... 6 years, 4 months ago

1Thank You

Shivam Mishra 6 years, 4 months ago

Keb tk aoge 10se bhi jada ho gye

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Dafa hi

Posted by Rekha Dalia 6 years, 4 months ago

CBSE > Class 10 > Science

2 answers

Navneet Kumar 6 years, 4 months ago

Hello

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Apoorva ..... 6 years, 4 months ago

Dafa kon h

2Thank You

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Short note on human evolution.

Posted by Anjali Yadav 6 years, 4 months ago

CBSE > Class 10 > Science

1 answers

Yogita Ingle 6 years, 4 months ago

Human evolution is the evolutionary process leading up to the appearance of modern humans. Scientific evidence shows that the physical and behavioral traits are shared by all people originated from apelike ancestors >

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What are plant hormone

Posted by Sandeeo Singh 6 years, 4 months ago

CBSE > Class 10 > Science

2 answers

Aadya Singh ? 6 years, 4 months ago

The function of Control and coordination in plants is performed by a chemical substances are called plant hormones.

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Aarti Rana 6 years, 4 months ago

The chemical messengers in plant which help in their growth and development

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What is oxidatio and reduction???

Posted by Ishita Chochan Ishu 6 years, 4 months ago

CBSE > Class 10 > Science

4 answers

S S 6 years, 4 months ago

The process in which either oxygen is added to a substance or hydrogen is remove from substance is called oxidation. The process in which either hydrogen added to a substance or oxygen is remove from substance is called reduction.

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Aarti Rana 6 years, 4 months ago

Oxidation-adding of oxygen and reductin is removal of oxygen

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Aadya Singh ? 6 years, 4 months ago

The addition of hydrogen to a substance and the removal of oxygen from a substance is called reduction.

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Aadya Singh ? 6 years, 4 months ago

the addition of oxygen to a substance and removal of hydrogen from a substance is called oxidation.

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What is exathermic reaction and endhermic reaction ??