Ask questions which are clear, concise and easy to understand.
Ask QuestionPosted by Ritika Jangra 3 years, 11 months ago
- 2 answers
Posted by Umang Gupta 3 years, 11 months ago
- 3 answers
Shakti Kumar 3 years, 11 months ago
Yogita Ingle 3 years, 11 months ago
Centrifugation is the process that uses centrifugal force for the separation of two liquids in a mixture. In this process, the denser component of the mixture migrates away from the axis and the lighter component migrates towards the axis.
Let us understand this process with the example of milk, as the tubes containing the milk are rotated, the heavier milk is pulled outward against the wall, whereas, the lighter cream is collected in the middle. Both the components are then collected separately.
Alka Yadav 3 years, 11 months ago
Posted by Learningqueen Nikita 3 years, 11 months ago
- 1 answers
Yogita Ingle 3 years, 11 months ago
| These are solids at room temperature except mercury | These exist in all three states |
| These are very hard except sodium | These are soft except diamond |
| These are malleable and ductile | These are brittle and can break down into pieces |
| These are shiny | These are non-lustrous except iodine |
| Electropositive in nature | Electronegative in nature |
| Have high densities | Have low densities |
Posted by Joyeeta Mondal 3 years, 11 months ago
- 1 answers
Yogita Ingle 3 years, 11 months ago
- Tracheids are elongated tube-like dead cells with oblique end walls. The walls are hard and lignified. Vessels are placed one upon the other and their end walls are either absent or possess perforations.
- They help in conduction of water and minerals. Xylem parenchyma are living parenchymatous cells present in the xylem. They help in the lateral conduction of organic solutes and the storage of food reserves.
- Xylem fibers are lignified fibers present in the xylem which provide mechanical strength to the plant body.
Posted by Athresh M Kumar 3 years, 11 months ago
- 0 answers
Posted by Tanmay Goyal 3 years, 11 months ago
- 1 answers
Yogita Ingle 3 years, 11 months ago
Properties of solids
- Solid has fixed volume.
- Solid has fixed shape.
- Solid has high density.
- Solids are heavy.
- Solid does not flow.
Properties of liquid
- Liquid has definite volume.
- Liquid has no definite shape.
- Liquid gets the shape of container in which it is kept.
- Liquid cannot be compressed much.
- Liquid has less density compare to solid.
- Liquid is lighter than solid.
- Liquid flows and hence is called fluid.
Properties of gas
- Gas has indefinite shape
- Gas has no fixed volume.
- Gas gets the shape and volume of container.
- Gas fills the container completely.
- Gas has very low density.
- Because of low density gas are light.
- Gas can flow easily and hence are called fluid.
Posted by Trishla Jain 3 years, 11 months ago
- 3 answers
Trishla Jain 3 years, 11 months ago
Yogita Ingle 3 years, 11 months ago
| Size of the particles | < 1nm | 1– 1000nm | >1000nm |
| Nature | Homogeneous | Heterogeneous | Heterogeneous |
| Filterability(Diffusion through parchment paper) | Particles of true Solution diffuse rapidly through filter paper as well as parchment paper. | Colloidal particles pass through filter paper but not through parchment paper. | Suspension particles do not pass through filter paper and parchment paper. |
| Visibility | Particles of True Solution are not visible to naked eye. | Colloidal particles are not seen to naked eye but can be studied through ultra microscope. | Suspension particles are big enough to be seen by naked eye. |
| Tyndall effect | True Solution does not show Tyndall effect. | Colloids shows Tyndall effect. | Suspension may or may not show Tyndall effect. |
| Appearance | Transparent | Translucent | Opaque |
Posted by Trishla Jain 3 years, 11 months ago
- 1 answers
Yogita Ingle 3 years, 11 months ago
Different properties of solutions are as follows:
- It is a homogeneous mixture.
- Its particles are too tiny and have a diameter less than 1 nm.
- The particles are not visible to naked eyes.
- Particles don’t scatter a beam of light passing through it and hence the path of the light is not visible.
- Solutes are inseparable from the mixture and do not sediment. A solution is stable.
- The components of a mixture cannot be separated using filtration.
Posted by Himanshu Pathak 3 years, 11 months ago
- 1 answers
Gaurav Seth 3 years, 11 months ago
Protection: As it covers the entire body surface, it is the first line of defence against any kind of mechanical injury, chemical exposure, excessive fluid loss and infections. Ciliary projections present in the nose or upper respiratory tract, trap the dust particles and prevent it from entering the body
Absorption: The epithelial lining of the digestive tract absorbs water and nutrients
Exchange of substances: Epithelial tissue regulates the exchange of substances between body and external environment as well as the internal exchange between different parts of the body. Everything that enters the body or enters the bloodstream by absorption has to cross the epithelial barrier
Sensation: Sensory receptors are present in the epithelial tissue of the nose, eyes and ears, taste bud, etc. that help in transmitting signals from the external stimuli to the brain
Secretion: Various glands made up of epithelial cells secrete hormones, enzymes, saliva, mucus, sweat, etc.
Posted by Mannat Maji 3 years, 11 months ago
- 1 answers
Gaurav Seth 3 years, 11 months ago
A N S W E R : Congenital d i s e a s e s
Congenital diseases are those diseases which are present in the child from birth. Common examples include Cystic fibrosis, Down syndrome, Haemophilia, etc.
Posted by Chaitali 1612 3 years, 11 months ago
- 2 answers
Yogita Ingle 3 years, 11 months ago
Water hyacinth floats on surface of water because the parenchyma tissue present in water hyacinth has specialized tissue modification which is called Aerenchyma. This tissue has large air cavities due to which it provides the buoyancy to the plant and helps to float in the water.
Water hyacinth is large aquatic plant which doesn’t has any attachment with the bottom of water body and it always remains visible floating on surface of water body.
Gaurav Seth 3 years, 11 months ago
A n s w e r :
W a t e r hyacinth floats in water due to presence of large air cavities in the parenchyma tissue. These specialized parenchyma tissue are called parenchyma.
Posted by Chaitali 1612 3 years, 11 months ago
- 2 answers
Yogita Ingle 3 years, 11 months ago
When we wash clothes, our hands are exposed to water for a long time. Our hands behave as a hypertonic solution and the outside of our hands behave as a hypotonic solution. Our skin behaves as a semi-permeable membrane as it is porous. So actually the water is not absorbed here just leaving and thus it shrinks. Soap solution is a hypertonic solution i.e., more concentrate than our skin cells. The process is called exosmosis.
Gaurav Seth 3 years, 11 months ago
When we wash clothes, our hands are exposed to water for a long time. Our hands behave as a hypertonic solution and the outside of our hands behave as a hypotonic solution. Our skin behaves as a semi-permeable membrane as it is porous. So actually the water is not absorbed here just leaving and thus it shrinks. Soap solution is a hypertonic solution i.e., more concentrate than our skin cells. The process is called exosmosis.
Posted by Pata Monalisha 3 years, 11 months ago
- 3 answers
Himanshu, Tarun,Sakshi Yadav 3 years, 11 months ago
Ishita Budhwar 3 years, 11 months ago
Gaurav Seth 3 years, 11 months ago
There are several reasons for this.
Atmosphere :
Earth has a breathable atmosphere. Oxygen is the gas that is required for the life of most creatures. This is present in Earth's atmosphere and also in water. Oxygen is constantly put into the atmosphere by plants and trees. Earth's atmosphere also contains a small amount of carbon dioxide. This is a poisonous gas which makes up most of the atmosphere of planets like Venus and Mars and makes them unable to support human life. However, its smaller presence on Earth is useful as it helps to moderate the planet's temperature and is absorbed by plants during photosynthesis to produce oxygen. Earth's atmosphere is kept on the planet by its pull of gravity. Mars and Mercury are too small to keep atmosphere. As a result, Mercury has no atmosphere, and Mars' atmosphere is very thin, containing gases which have not managed to escape into space yet. Earth's atmosphere is thick enough to prevent poisonous rays of radiation from getting through it (this is what has happened on Mars).
Temperature :
Earth has a suitable temperature (amount of heat). Earth is situated from the sun at such a distance, that it receives perfect amount of solar energy from the sun, such that the life can sustain.
The temperature is maintained by the moderate amount of carbon dioxide in the planet's atmosphere, which is constantly refreshed whenever there is a volcanic eruption. The temperature on Earth does not go from one extreme to the other either. Mercury can be anything from 200°c below freezing to 375°c above. At 375°c, water would only exist as a gas, and the planet would be completely dry. Venus has a surface temperature of 480°c, which would be much too hot for anybody to live in. Mars, although it can reach 25°c, can be as cold as -140°c, a temperature which would freeze blood and water. The other planets are even colder.
Water :
Earth has water! Water is believed to be the most important chemical necessary for life. It contains the oxygen needed for life and it allows life-providing molecules to move around easily. Water on Earth can be found anywhere, in its three states.
Sunlight and photosynthesis :
All planets receive light from the Sun, but no planet uses it as usefully as Earth. Trees and plants on the planet produce oxygen through a process called photosynthesis. Plants need the Sun to grow. Something else which helps the plants to photosynthesise on Earth is the length of time the planet takes to spin once on its axis. Taking just under 24 hours means that each side of the planet receives sunlight regularly. If we look at a planet like Venus, which takes 243 days to spin on its axis, it means that for a large period of time certain parts of the planet are in complete darkness. So even if the planet could support life, it would struggle to do so.
Posted by Aditi Baspar 3 years, 11 months ago
- 3 answers
Manyata Joshi 3 years, 11 months ago
Posted by Prakash Rathore 3 years, 11 months ago
- 5 answers
Posted by Lalruatzeli Cvanlalruatzeli 3 years, 11 months ago
- 0 answers
Posted by Yogesh Dahiya 3 years, 11 months ago
- 3 answers
Posted by Ojhal Sharma 3 years, 11 months ago
- 0 answers
Posted by Surjeet Mohanty 3 years, 11 months ago
- 1 answers
Suchitra Sen 3 years, 11 months ago
Posted by Nishu Kashyap 3 years, 11 months ago
- 1 answers
Apurva Satkar 3 years, 11 months ago
Posted by ꧁༒☬ℜ؏Αꮮ☬༒꧂ ꧁༒☬Ꮶιηgs☬༒꧂ 3 years, 11 months ago
- 1 answers
Yogita Ingle 3 years, 11 months ago
We have,
Mass of the rifle, m₂ = 3 kg
Mass of the Bullet, m₁ = 0.03 kg
The velocity of the bullet, v₁ = 100 m/s
Time taken by bullet to move through the barrel, t = 0.003 s
So,
Initial velocity of rifle, u₂ = 0 m/s.
Initial velocity of bullet, u₁ = 0 m/s.
Final velocity of bullet, v₁ = 100 m/s.
Final velocity of rifle = v₂ m/s.
Now, we know from the law of conservation of momentum,
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
So,
(0.03 x 0) + (3 x 0) = (0.03 x 100) + (3 x v₂)
0 = 3 + 3.v₂
v₂ = -1 m/s
Therefore, acceleration of the rifle is given by,
So,
The Force experienced by rifle, therefore, would be,
F = m.a
F = 3.(-333.33)
F ≈ 1000 N
Posted by Sonu Panjiyar 3 years, 11 months ago
- 4 answers
Gaurav Seth 3 years, 11 months ago
The weight of an object is the gravitational force acting on it. Since, the gravitational force of the moon is 1 / 6th of earth. The weight of an object on moon is also 1 / 6th as compared to its weight on earth.
Posted by Satyajeet Paswan 3 years, 11 months ago
- 5 answers
Posted by Malek Sakil 3 years, 11 months ago
- 5 answers
Posted by Anubhav Yadav 3 years, 11 months ago
- 5 answers
Posted by Archit Dubey 3 years, 11 months ago
- 1 answers
Gaurav Seth 3 years, 11 months ago
No. of Particles = given mass/Gram Atomic/Molecular Mass x Avogadro's Number
Gram atomic mass of oxygen = 16u (given)
Given mass = 1g
No. of atoms = 1/16 x 6.022 x 10²²
= 0.376375 x 10²² = 3.763 x 10²¹ atoms
So, X = 3.763 x 10²¹
Similarly, for aluminum,
No of atoms = 1/27 x 6.022 x 10²²
≈ 2.230 x 10²¹ atoms
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
Neha Jangid ??? 3 years, 11 months ago
0Thank You