Larynx is the Synonym of voice box which is present in our throat and helps us to talk. Hope it helped ??

Lyranx is the synonym of vouce box

Larynx is the Synonym of voice box which is present in our throat and helps us to talk...

Variable

Tera bap

The function of a nerve cell is to transmit messages to the brain and also to take away messages from the brain to the receptor organs. Thus, it controls the working of different parts of the body.

Bulb is a source of energy invented by Thomas Edison as used for light it can find anywhere.

Apart from lighting, the light bulbs are used in electronic items as an indicator, traffic signals, indicator lights in cars, etc.

(a) Preparation of soil Preparation of soil is the first step before growing of crop. It helps to turn the soil and loosen it to allow the roots to penetrate deep into it. The loosening of the soil helps in the growth of several soil microbes, earthworms etc., which enrich the soil with humus and other essential nutrients. The process of turning and loosening is called ploughing. This is done using a plough, hoe and cultivators. (b) Sowing Sowing is the process of putting the seeds into the soil for growing crops. We need to use quality seeds for sowing. Sowing is done manually using mechanical equipment like Seed Drill. Seeds of few plants like rice are first grown in a separate area and then transplanted in the fields. (c) Weeding In a field many other undesirable plants may grow along with the crop. These undesirable plants are called weeds. Farmers use many ways to remove weeds. Methods to control weeds are: tilling before sowing of crops, physical removal of weeds by uprooting or cutting them close to the ground, using certain chemicals called weedicides etc. (d) Threshing Threshing is the process of separating grains or seeds from chaff. It is done after harvesting the crop. It is usually carried out with the help of a machine known as ‘Combine’. This machine is a combined harvester and thresher. It harvests plants as well as cleans grains.

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(a) Preparation of soil

Preparation of soil is the first step before growing of crop. It helps to turn the soil and loosen it to allow the roots to penetrate deep into it. The loosening of the soil helps in the growth of several soil microbes, earthworms etc., which enrich the soil with humus and other essential nutrients. The process of turning and loosening is called ploughing. This is done using a plough, hoe and cultivators.

(b) Sowing

Sowing is the process of putting the seeds into the soil for growing crops. We need to use quality seeds for sowing. Sowing is done manually using mechanical equipment like Seed Drill. Seeds of few plants like rice are first grown in a separate area and then transplanted in the fields.

(c) Weeding

In a field many other undesirable plants may grow along with the crop. These undesirable plants are called weeds. Farmers use many ways to remove weeds. Methods to control weeds are: tilling before sowing of crops, physical removal of weeds by uprooting or cutting them close to the ground, using certain chemicals called weedicides etc.

(d) Threshing

Threshing is the process of separating grains or seeds from chaff. It is done after harvesting the crop. It is usually carried out with the help of a machine known as ‘Combine’. This machine is a combined harvester and thresher. It harvests plants as well as cleans grains.

A. Microscope B. Unicellular C. Used for moving D. Other microorganism are also found.

1

1.Microscope is uses to study microbes. 2. Amoeba is a unicellular organisms. 3. Pseudopodia help in ingestion of food. 4. The values expected from them is that from water and soil they found more other things then amoeba.

1.Microscope is uses to study microbes.

2. Amoeba is a unicellular organisms.

3. Pseudopodia help in ingestion of food.

4. The values expected from them is that from water and soil they found more other things then amoeba.

As we know for burning oxygen is important that is obtained from air .They make a thick blanket which doesn't allow to pass air from which supply of oxygen is cut

CO2​ is a non-combustible gas and it is also non-supporter of combustion.

 

CO2​ is a non-combustible gas and it is also non-supporter of combustion. It extinguishes fire in two ways: 

1. Since it is heavier than oxygen, it covers the fire like a blanket and cuts off the contact between oxygen and fuel. 

2. In cylinders, CO2​ is kept in the liquid form. When released, it expands enormously and cools down. This brings down the temperature of the fuel, which helps in controlling the fire. 

Because they react from oxygen which is found in air

Na and K are very reactive metals and kept in kerosene oil to prevent it from coming in contact with oxygen and moisture as they react to form their hydroxides. This is an exothermic reaction and lot of heat is generated so both the metals are kept in kerosene oil.

Na and K are very reactive metals and kept in kerosene oil to prevent it from coming in contact with oxygen and moisture as they react to form their hydroxides. This is an exothermic reaction and lot of heat is generated so both the metals are kept in kerosene oil.

H2So4

Metal: gold tin iron Non metal: carbon hydrogen sulphur

Metals : GOLD, TIN, IRON Non metal : CARBON, PLASTICS, POLYTHENE

M e t a l s: Iron, copper, aluminium, zinc, gold, silver, sodium, potassium, nickel, cobalt, tin, ,mercury etc

Non M e t a l s: Carbon,sulphur,helium,hydrogen,phosphorus,fluorine,chlorine etc.

CNG compressed natural gas LPG liquid petroleum gas

✨Compressed natural gas ✨Liquefied petroleum gas

CNG-Compressed Natural Gas.

LPG – Liquefied Petroleum Gas.

LPG – Liquefied Petroleum Gas. 

CNG-Compressed Natural Gas.

LED is Light Emitting Diode which glows even for a small or low value of current. Light-emitting diodes, or LEDs, are widely used as a standard source of light in electrical equipment. Uses : Used for TV back-lighting Uses in displays

LED is Light Emitting Diode which glows even for a small or low value of current. Light-emitting diodes, or LEDs, are widely used as a standard source of light in electrical equipment. 

Uses :

• Used for TV back-lighting
• Uses in displays
• Used in automotive
• LEDs used in the dimming of lights

Outer Inner

Innermost zone Outermost zone

a) outer b) innermost

The outer zone is blue in color, due to complete combustion,. This zone is the hottest zone.

The least hot region of the flame is innermost zone. This inner zone is black in color due to the presence of unburnt wax vapors.

Good gaurav Seth ????????????

the question has been answered as per class 8

the 4th friction is Fluid friction

Sorry if wrong ??

There are four types of friction. Friction is the resistance to motion of one object moving relative to another.

Friction is defined as the force that opposes the motion of a solid object over another. 

Friction is of 3 types

1)Static friction

2)Sliding friction

3)Rolling friction

Static friction

The maximum fictional force present between any two objects when one object just tends to move or slip over the surface of the other object ,is called static friction.Static friction is a kind of starting fiction because an object just tends to start moving, it does not actually move.

Sliding friction

The frictional force present when one object moves slowly or slides over the surface of another object is known as sliding friction

Rolling friction

When an object rolls over the surface of another object ,the resistance to its motion is called rolling friction.

It is always easier to roll than to slide an object over another object.So rolling friction is much less than the sliding friction.

Balance diet is a healthy diet in which our body maintain with all nutrition in a proper way.

Balanced diet is a diet in which we take all the nutrients judicially. Like - carbohydrates,fats and so on

A push or a pull acting on an object is called force

A force is a push or pull upon an object resulting from the objects interaction with another object .

Force is the change momentum of the body with respect to time

A motion of push or pull is called friction

In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object with mass to change its velocity, i.e., to accelerate. Force can also be described intuitively as a push or a pull. A force has both magnitude and direction, making it a vector quantity.

The amount of heat produced by the complete burning or combustion of 1Kilogram of a fuel is called its calorific value.

Different fuels produce different amounts of heat on burning.

The amount of heat produced by the complete burning or combustion of 1Kilogram of a fuel is called its calorific value.

The calorific value of a fuel is expressed in the unit of Kilojoules per kilogram.

For Ex:The calorific value of kerosene is 45000KJ/Kg  means when 1Kg of kerosene is burned completely then 45000 KJ of heat energy is produced.

The calorific value of a fuel is also known as heat value.

The calorific value of LPG is 55000KJ/Kg  means when 1Kg of LPG is burned completely then 55000 KJ of heat energy is produced.

The role of Bacteria in Agriculture:

• Nitrogen-fixing bacteria

The conversion of atmospheric nitrogen into forms of nitrogenous compounds usable by plants is. bacteria living in the root nodules of legume plants fix nitrogen from the atmosphere. Microorganisms in the soil convert atmospheric nitrogen into ammonium compounds, thereby enabling the plants and animals. Nitrogen is an essential constituent of nucleic acids, chlorophyll and vitamins. Rhizobium, Azobacter and Clostridium are species of bacteria which are capable of converting atmospheric nitrogen into forms usable by plants. Plants cannot use nitrogen in elemental form; hence the role of the nitrogen-fixing bacteria becomes very important

• Nitrifying bacteria

Nitrifying bacteria convert nitrogenous waste from dead plants and animals present in the soil into nitrates by the process called as nitrification. In this process, certain ammonifying bacteria like Bacillus and Clostridium first convert nitrogenous waste into ammonia. This ammonia is then converted into ammonium compounds by the same ammonifying bacteria. The ammonium compounds are then converted into nitrites by nitrifying bacteria such as Nitrosomonas, Nitrococcus and then into nitrates by nitrifying bacteria such as Nitrobacter.

• Denitrifying bacteria

Denitrifying bacteria like Pseudomonas putida and Bacillus subtilis are also present in the soil. These bacteria break down nitrates in the soil and release free nitrogen gas, which then enters the atmosphere.

• Scavenging Role

 Saprophytic bacteria obtain food from organic remains such as animal excreta, fallen leaves, meat etc. They decompose these substances by the action of digestive enzymes aerobically or anaerobically (known as fermentation). Thus they help in sanitation of nature, so also known as scavengers. E.g.Pseudomonas.

• Production of fuel

Bacteria, while converting animal dung and other organic wastes to manure, help in the production of fuel that is a must in gobar gas plant.

• Disposal of sewage

 Bacteria help in disposal of sewage by decomposing it and thus, help in environmental sanitation.

Plant Cell	Animal Cell
Large, with a distinct outline.	Usually small, with a less distinct outline.
Cell wall is present. The cell membrane is surrounded by the cell wall.	Cell wall is absent.
Plastids are present.	Plastids are absent.
A large vacuole is present in the centre.	Vacuoles are absent; however, if present, they are small.
Centrosome is absent.	Centrosome is present.
Cytoplasm is not so dense.	Cytoplasm is denser and more granular and almost fills the entire cell.
Golgi apparatus has smaller units called dictyosomes.	Golgi apparatus is highly complex and prominent.

Hertz

Hertz is the full form of hz

Unit of frequency is Hz. Full form of Hz is hertz

Hertz

A greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect on planets. The primary greenhouse gases in Earth's atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3).

Greenhouse gases include carbon dioxide, methane, nitrous oxide and other gases that accumulate in the atmosphere and create the heat-reflective layer that keeps the Earth at a livable temperature. These gases form the insulation that keeps the planet warm enough to support life.

Difference between metals and non-metals:

Metals	Non-metals
Metals are malleable and ductile.   They are good conductors of heat and electricity. They are hard. They are lustrous. They are sonorous.	Non-metals are not malleable and ductile. They are poor conductors of heat and electricity. They are soft. They are not lustrous. They are not sonorous.

 

Difference between metals and non-metals:

Metals	Non-metals
Metals form basic oxides. They react with water to produce hydrogen gas except copper, silver and gold. They react with dilute acids to produce hydrogen gas except copper, silver and gold.	Non-metals form acidic oxides. They do not react with water.     They do not react with dilute acids.

 

 

A cell consists of three parts: the cell membrane, the nucleus, and, between the two, the cytoplasm. Within the cytoplasm lie intricate arrangements of fine fibers and hundreds or even thousands of miniscule but distinct structures called organelles.

Parts

Cell Membrane

• The outer boundary of cell enclosing nucleus and cytoplasm is called cell membrane or plasma membrane.
• The cell membrane separates cell and its components from the outside environment. Also, it separates cells from one another.
• The cell membrane is porous to specific ions and organic molecules and controls the movement of substances in and out of the cells. Therefore, the cell membrane is selectively permeable.
• It gives shape to the cell.
• In plant cells, there is an additional thick layer surrounding cell membrane called cell wall. The cell wall gives rigidity to the cell. It protects the plant cells against different environmental conditions like high wind speed, atmospheric pressure, etc. We can observe cells in the leaf peel of Tradescantia, Elodea, Rhoeo or onion peel.

Cytoplasm

• It is a jelly like fluid present between nucleus and cell membrane.
• Organelles like chloroplast, mitochondria, golgi apparatus, ribosomes, etc. are dispersed in cytoplasm.

Nucleus

• Generally, it is spherical in shape and located in the center of the cell.
• A membrane called nuclear membrane separates nucleus from the cytoplasm.
• The nucleus is the control center as it regulates all the activities of the cell.
• When nucleus is observed under microscope, a small spherical body in the nucleus was seen and called nucleolus. Also, it contains thread-like structures called chromosome. These chromosomes carry genetic material (genes) and help in inheritance/transfer of characters from parents to offspring.
• The nuclear membrane is porous and allows the movement of materials between cytoplasm and nucleoplasm (Nucleolus and Chromosomes).

• Cell: The fundamental unit of structure and function in living organism.

Example: Blood cells, Nerve cells, etc.

Cell is made up of basically 3 components:  Cell Membrane, cytoplasm and nucleus.

Cell Membrane

• The outer boundary of cell enclosing nucleus and cytoplasm is called cell membrane or plasma membrane.
• The cell membrane separates cell and its components from the outside environment. Also, it separates cells from one another.
• The cell membrane is porous to specific ions and organic molecules and controls the movement of substances in and out of the cells. Therefore, the cell membrane is selectively permeable.
• It gives shape to the cell.
• In plant cells, there is an additional thick layer surrounding cell membrane called cell wall. The cell wall gives rigidity to the cell. It protects the plant cells against different environmental conditions like high wind speed, atmospheric pressure, etc. We can observe cells in the leaf peel of Tradescantia, Elodea, Rhoeo or onion peel.

Cytoplasm

• It is a jelly like fluid present between nucleus and cell membrane.
• Organelles like chloroplast, mitochondria, golgi apparatus, ribosomes, etc. are dispersed in cytoplasm.

Nucleus

• Generally, it is spherical in shape and located in the center of the cell.
• A membrane called nuclear membrane separates nucleus from the cytoplasm.
• The nucleus is the control center as it regulates all the activities of the cell.
• When nucleus is observed under microscope, a small spherical body in the nucleus was seen and called nucleolus. Also, it contains thread-like structures called chromosome. These chromosomes carry genetic material (genes) and help in inheritance/transfer of characters from parents to offspring.
• The nuclear membrane is porous and allows the movement of materials between cytoplasm and nucleoplasm (Nucleolus and Chromosomes).

Curd,

Some simple example are curd and yogurt.

hmm

Good ConductorsBad ConductorsGood conductors are those materials which allow electricity to pass through them easily.Bad conductors are those materials which do not allow electricity to pass through them

I hope my answer will help you. *Difference between Good Conductor and Bad Conductor of Electricity ~ @Good Conductors Bad Conductors Good conductors are those materials which allow electricity to pass through them easily. @ Bad conductors are those materials which do not allow electricity to pass through them easily.

Hope it helps...?

A material that allows electricity to pass through it easily is called a conductor. Metals, especially silver, are good electrical conductors. Materials like glass and plastic are poor electrical conductors, and are called insulators.

Good Conductors Bad Conductors Good conductors are those materials which allow electricity to pass through them easily. Bad conductors are those materials which do not allow electricity to pass through them easily.

Hoe

Plough ,hoe

Plough, hoe, cultivator

Plough hoe

Plough, Hoe & Cultivator are three important tools which help in soil preparation.

Plough

Tool used for ploughing . It is made of iron/ wood. It is pulled by a pair of animals like cows/ oxen/ horses and operated by the farmer through the handle.  It has 3 important parts:

• Ploughshare: strong triangular iron strip
• Plough shaft: long log of wood
• Beam: stand placed on animals’ neck

Hoe

Hoe is a tool used for loosening soil. It is made of wood or iron. A strong iron plate attached to the long rod acts like a blade and helps to loosen the soil. It is also pulled by animals.

Cultivator

Cultivator is a tool used for ploughing. Manual as well as tractor driven cultivators are used. Tractor driven cultivators are fast, thus save time and also saves human labor.

Process Of Frictional Distillation: Fractional distillation separates a mixture into a number of different parts, called fractions. A tall fractionating column is fitted above the mixture, with several condensers coming off at different heights. ... The crude oil is evaporated and its vapours condense at different temperatures in the fractionating column. I hope my answer will help you.

This method is used to separate the mixture of two miscible liquids where difference between their boiling points is less than 25 ºC. Also to separate a mixture of two or more miscible liquids for which the difference in boiling points is less than 25 K, fractional distillation process is used, for example, for the separation of different gases from air, different factions from petroleum products etc. The apparatus is similar to that for simple distillation, except that a fractionating column is fitted in between the distillation flask and the condenser. A simple fractionating column is a tube packed with glass beads. The beads provide surface for the vapours to cool and condense repeatedly, as shown in following figure.

Petroleum was formed from dead organisms that got buried in the sea millions of years ago. These dead bodies got covered with layers of sand and clay. Lack of air, high temperature, and high pressure transformed these dead organisms into petroleum and natural gas.

Coal was formed by the decomposition of large land plants and trees buried under the earth 300 million years ago.About 300 million years ago,the earth had dense forest s in low-lying wet land areas.Due to natural processes like earthquake,volcanoes and floods etc these forests were buried under the surface of earth.As more soil deposited over them,they were compressed.The temperature also rose as they sank deeper and deeper.Due to high pressure and temperature inside the earth,and in the absence of air,the woods of buried trees was slowly converted into soil.

The slow process by which the dead plants buried deep under the earth have become coal is called Carbonisation.Since coal was formed from remains of plants therefore coal is called a fossil fuel.

When heated in air,coal burns and produce,mainly carbon dioxide gas.A lot of heat energy is also produced during the burning of coal.

Coal is an important because it can be used as a source of heat energy as such,or it can be converted into other forms of energy such as coal gas,coke or electricity.