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Define evolution

Posted by Basmath Ali Shahir 7 years, 3 months ago

CBSE > Class 09 > Science

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Explain the type of body cavity in nematodes and platyhelminthes

Posted by Queen_ Of _My _Heart 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Mishthi Jaiswal 7 years, 3 months ago

Body cavity us also known as coelom. In platyhelminthes the coelom is absent i.e. they are acoelomate and in nematoda false coelom is present i.e. they are pseudocoelomate.

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A body travels 3 km. It then takes a right turn and travels 4 km. The displacement would be 5 km. How will 3km+4km=5km

Posted by Ved Jaw 7 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Vanshika Tyagi 7 years, 3 months ago

3km+4km=7km. That is distance not displacement Displacement is the shortest distance from initial position to final position.

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Amrita Tiwary 7 years, 3 months ago

Displacement is shortest distance from initial and here u find distance

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Aman Anshuman 7 years, 3 months ago

Here the displacement is 5 . But you find out the distance.

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Sir bone is composed of which type of matrix ?

Posted by Aman Anshuman 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Ved Jaw 7 years, 3 months ago

Calcium and phosphorous compound Bone is made up of a hard matrix

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sir what means connective tissue

Posted by Lakshy Choudary 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 7 years, 3 months ago

It protects and supports the body.
The cells are loosely spaced and embedded in an intercellular matrix.
The matrix may be jelly like, fluid, dense or rigid.
The nature of matrix differs in concordance with the function of the particular connective tissue.

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Define reverberation

Posted by Shekhar Singh 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Gaurav Seth 7 years, 3 months ago

Many multiple echoes of a sound can be produced are called as reverberations. Reverberation is the phenomenon of overlapping of sound caused by multiple reflections. Reverberation causes the overlapping of several reflected waves. If the time gap between the reflected waves is so short that these cannot be distinguished. So we hear multiple noisy sounds. Example: reverberation of sound occurs in small cave almost the gap between the walls is approximately 17 m.

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What is a upthurst

Posted by Vibhanshu Sahrawat 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Ankit Raj 7 years, 3 months ago

The upward force exerted by a fluid (liquid) is called upthurst. Also,buoyant force is also known as upthurst

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Gaurav Seth 7 years, 3 months ago

The upward force experienced by a body when it is partly or wholly immersed in a fluid is called buoyant force or upthrust. (it is also defined as the weight of the fluid displaced by the immersed part of the body.)

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How I can learn composition of Atoms of first 18 elements easily

Posted by Amandeep Sehrawat 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Aanchal Jaiswal 7 years, 3 months ago

Firstly you learn the elements then atomic no. And then atomic mass you learn first 1-5 elements... Then 6-10 like this you learn the 18 or more..

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What is the PH value of human blood

Posted by Anuj Kumar 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Amandeep Sehrawat 7 years, 3 months ago

A pH of 7.0, in the middle of this scale is nutural . Blood is normally slightly basic,alkaline, with a pH range of7.35 to7.45

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Anuj Kumar 7 years, 3 months ago

The PH value of human blood is 7.4

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What is archimedies principle

Posted by Narendra Pratap 7 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Rupinder Kaur 7 years, 3 months ago

It states that when a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it.

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Gaurav Seth 7 years, 3 months ago

Archimedes' principle states that the buoyant (upthrust) force exerted on a body submerged in a fluid, whether fully or partially, is equal to the weight of the fluid that the body displaces. One of the most useful discoveries to mankind in the field of physics is Archimedes’ principle. Based on this principle, a device called a hydrometer was developed which helps in measuring the density of liquids with ease. Archimedes’ principle states that “When a body is immersed completely or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by the body.”According to the principle, a solid that floats or is immersed in a liquid appears to lose its weight which is equal to the weight of the liquid displaced by the solid. Whether a given solid drowns or not in a given liquid depends on the density of the solid in comparison with that of the liquid.For an easy approach, we consider the relative density of the substance, which is the ratio of the density of the substance to the density of water, which obviously has no units but a mere number. If the relative density of the given solid is greater than that of the given liquid, it drowns in the liquid as there is a net downward force on the solid after it gets completely immersed in the liquid. If the relative density of the liquid and that of the solid are equal, then the solid just floats or drowns. This implies that the solid immerses in the given liquid and stays suspended at the kept position. If the relative density of the given solid is lesser than that of the given liquid, it floats in the liquid. This happens due to the up thrust or buoyant force of the liquid acting on the solid. The relative density of a floating solid in a given liquid gives the measure of the percentage of the solid that lies below the surface of the liquid.The “relative density” or “specific gravity” of a substance is defined as the ratio of its density to the density of water at 4 degrees Celsius. Relative density = Density of substance Density of water at 4 ℃ This can be expressed in many ways. If the numerator and the denominator are both multiplied by “volume”, then we get the expression relative density is equal to the ratio of “mass of the substance” to “mass of water of the same volume.”Relative density = Mass of substanceMass of water of same volume Again, when the numerator and the denominator are both multiplied by acceleration due to gravity “g”, the expression becomes:Relative density = Weight of substanceWeight of water of same volume When the substance is immersed in water, it displaces water of volume equal to its own volume. According to Archimedes’ principle, the apparent loss of weight of a body immersed in water is equal to the weight of the water displaced. Therefore:Relative density = Weight of substance Apparent loss of weight when immersed in water This expression can be used to find the relative density of a solid body. In order to find the relative density of a liquid, a solid body is taken and its weight is found in air. Then, the weight of the same body is found when it is completely immersed in the liquid whose relative density is to be found. Finally, the weight of the body is found by immersing it completely in water. The relative density of the liquid can be found using the expression: Relative density = Loss of weight of a solid body when immersed in liquid Loss of weight of the same body when immersed in water

The relative density of a substance is the ratio of density of the substance to the density of water.
Relative density should be calculated using the same system of units for the substance as well as water.
A hydrometer uses Archimedes’ principle to determine the density of any liquid.
Archimedes’ principle is also used in designing ships and submarines.

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Narendra Pratap 7 years, 3 months ago

Answer

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Compare the properties of electron,proton and neutron

Posted by Latika Deka 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Aanchal Jaiswal 7 years, 3 months ago

Electron - has negative charge. Proton- has positive charge. Neutron- has zero charge.

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deference between compression and rarefaction

Posted by Satvir Singh Shekhawat 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Mohit Gedam 7 years, 3 months ago

Compression and rarefactions are both the concepts of longitudinal sound waves. Compression js a region in which pressure is high and rarefaction is a region having low pressure.

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Satvir Singh Shekhawat 7 years, 3 months ago

compression where the particles are clooser to each other rarefaction where the particles have more and more space

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Define 1 watt of power with example.

Posted by Krishna Rathod 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Mohit Gedam 7 years, 3 months ago

1 watt of power is said to be done when 1 joule of work is done in a unit second of time

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What is the difference between symptoms and signs???

Posted by Baona Paan 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

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Propagates of sound

Posted by Shalini Kumari 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

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How do the digestive system and respiratory system works

Posted by Shital Thakur 7 years, 3 months ago

CBSE > Class 09 > Science

0 answers

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Which type of plant tissue are xylem and phloem

Posted by Shital Thakur 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Tamanna . 7 years, 3 months ago

Xylem and phloem are complex type of tissue

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If 1.4 g of calcium oxide is formed by the complete decomposition of calcium carbonate ,then the amount of calcium carbonate taken and the amount of carbon dioxide formed will be respectively What?

Posted by Arya Katyayan 7 years, 3 months ago

CBSE > Class 09 > Science

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Why are we able to sip hot tea or milk faster from a saucer than a cup?

Posted by Abhinav Tiwari 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Arya Katyayan 7 years, 3 months ago

Because of the small surface area the evaporation of hot tea taken in the cup is slow ,cooling caused by evaporation is less ,and hence the hot tea or milk remains hot for longer time ,making it difficult to sip .on the other hand ,saucer has a large surface area. Due to the large surface area of hot milk taken in saucer ,the evaporation of hot tea from the saucer is faster.

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Saloni Kumar 7 years, 3 months ago

As saucer posses larger surface area than cup thus latent heat of vaporisation is faster in saucer hence we are able to sip hot tea or milk faster

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How many charge in proton

Posted by Sushila Kumari 7 years, 3 months ago

CBSE > Class 09 > Science

1 answers

Amrita Tiwary 7 years, 3 months ago

1.6×10 ka power _19

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What is more? In detail plz

Posted by Muskan Verma 7 years, 3 months ago

CBSE > Class 09 > Science

4 answers

Amrita Tiwary 7 years, 3 months ago

1 mole is 6.022×10ka power 23 no. Of particles nd molecules

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Muskan Verma 7 years, 3 months ago

Yaa i mean mole?

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Aanchal Jaiswal 7 years, 3 months ago

What more????

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Amrita Tiwary 7 years, 3 months ago

Mole..

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What is bulk phenomenon????

Posted by Amrita Tiwary 7 years, 3 months ago

CBSE > Class 09 > Science

2 answers

Amrita Tiwary 7 years, 3 months ago

Thoda brief me example

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Anjali Mehta 7 years, 3 months ago

It refers to the phenomenon where whole of the substance is ivolved in the process.

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What is acute and cronic dieases

Posted by Sneha Ingale 7 years, 3 months ago

CBSE > Class 09 > Science

3 answers

Aanchal Jaiswal 7 years, 3 months ago

(1) Acute disease:- which type of disease produce in The body for very short time is known as the acute disease. EX:- Sneezing, coughing, common cold etc. (2) chronic disease :- chronic disease therefore have very drastic long time effects on peoples health as compared to acute disease. Ex:- cancer HIV, AIDS, TB etc.

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Amrita Tiwary 7 years, 3 months ago

Like cancer, is chronic and headache , fever is acute disease

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Sunil Kumar 7 years, 3 months ago

Acute diseases last for short period of time. Their symptoms are sever and sudden but chronic diseases last for much longer period of time.Their symptoms are less sever and gradual

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What is electron?

Posted by Amrita Tiwary 7 years, 3 months ago

CBSE > Class 09 > Science

5 answers

Vanshika Tyagi 7 years, 3 months ago

An electron is a sub atomic fundamental particle which carry one unit negative charge . The negatively charge particle constisting the cathode rays are called Electrons .

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Rishita Singh 7 years, 3 months ago

Negatively charged sub atomic particle

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Gaurav Mishra 7 years, 3 months ago

Negative charged particle of an atom

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Aanchal Jaiswal 7 years, 3 months ago

Active passive (1) the hunter killed the lion. (1) (2) someone has cleaned the windows

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Amrita Tiwary 7 years, 3 months ago

Electron is sub atomic part of atom which consist of negative charge.