Introduction to makes up the atmosphere:
The atmosphere is the layer of gases, which surrounds the earth containing air mixed with the water vapor. In beginning, the earth was much bigger and much cooler with no atmosphere, but later as the earth, started contracting and it became smaller and warmer after the process of differentiation. During this phase gases like water vapor, hydrogen, helium, methane and ammonia were liberated which form the atmosphere. Gradually gases lighter than water like hydrogen and helium were formed. Free oxygen came into the atmosphere, with the evolution of autotrophs from heterotrophs. Here we discuss how the atmosphere of earth makes up.
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What makes up the atmosphere?
Atmosphere is composed of 78% nitrogen, 21% oxygen, 0.03% carbon dioxide and 0.07% of other gases. The percentage of water vapor in the atmosphere is variable. There are different layers in the atmosphere, let us know them:
Thermosphere: In this layer of the atmosphere, temperature increases until they approach 2000°F or 1090°C at noon. The air is even thinner at this altitude than it is in the upper atmosphere. In fact, there is practically a vacuum so that little heat can be conducted. It was once called the ionosphere because of ionization of molecules and atoms that occurs in this layer, mostly because of ultra violet, but also X rays and gamma rays. Ionization refers to the process whereby atoms are changed to ions through the removal or addition of electrons, giving them an electrical charge.
Mesosphere: Right below thermosphere lies Mesosphere. In this layer of the atmosphere, temperature tends to drop with the increase in the altitude.
Stratosphere: Just below Mesosphere lies Stratosphere. This is one of the main layers and the temperature here is stratified which means that the cool layers are below the warm ones.
Troposphere: This layer is the lowest one of all and contains maximum water vapour. This layer constitutes the most of atmosphere's mass which is upto 75%.
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Conclusion for the constituents of atmosphere:
From the above discussion, we can conclude that air is essential for the survival of life. Air contains nitrogen, oxygen, carbon dioxide, water vapor, argon, helium, methane, krypton, hydrogen, ozone, carbon mono oxide, sulphur dioxide, nitrous oxide, nitrogen dioxide, etc. Oxygen of the atmosphere is essential for photosynthesis. Nitrogen is also present in the atmosphere, which is taken by the some plants directly. Nitrogen is also used for the production of ammonia, which is used for making the fertilizers.
Friday, May 31, 2013
Photovoltaic Solar Cells
Introduction to photovoltaic solar cells
The first practical photovoltaic solar cell was made by selenium in 1954. This photovoltaic solar cell could convert only 1% of solar energy into electricity. Now these days, solar cells are usually produced from the semiconductor materials, such as silicon and gallium. Semiconductors are the materials, which do not allow to pass electricity at the normal conditions. The conductivity of the semiconductors increases appreciably if certain types of impurities are added. This addition of impurities is called doping.
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Photovoltaic Solar cell
A device, which converts sunlight directly into electricity, is called a solar cell. The semiconducting material to which a small quantity of a specific impurity is added is called doped semiconductor material. For example, when a small quantity of arsenic is added to ultrapure silicon, the silicon so obtained is termed as doped silicon. The conductivity of such semiconductor materials increases when light falls on them and a potential difference is developed between the two points in the semiconductor material. This cause a flow of a electric current. A single silicon solar cell of about 4 squared centimeter develops a potential difference of about 0.5 volt at 60 milliampere current. Due to this reason the solar cell is also called as photovoltaic cell. A single solar cell produces very small current at a small potential difference. So, in practice, we use a large number of solar cells connected together. This combination of a large number of solar cells is called a solar cell panel. A solar cell panel can provide stronger currents under high potential difference. Photovoltaic solar cells gained much importance in the last few decades due to the following reasons:
(i) The fossil fuels such as coal, petroleum etc are depleting very fastly, whereas the photovoltaic solar cells are renewable sources of energy.
(ii) Combustion of fossil fuels produce high air pollution and leads to green house effect whereas photovoltaic solar cells does not produce any type of pollution.
(iii) It is an energy source that is inexpensive.
(iv) These are used in remote areas very easily.
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Uses of Photovoltaic Solar Cells
(i) Photovoltaic solar cells are used in street lighting in rural areas.
(ii) Photovoltaic solar cells are used for operating water pumps for domestic and agricultural purposes.
(iii) Photovoltaic solar cells are used in satellites.
(iv) Photovoltaic solar cells are used to operate TV and other electrical appliances in our daily life.
The first practical photovoltaic solar cell was made by selenium in 1954. This photovoltaic solar cell could convert only 1% of solar energy into electricity. Now these days, solar cells are usually produced from the semiconductor materials, such as silicon and gallium. Semiconductors are the materials, which do not allow to pass electricity at the normal conditions. The conductivity of the semiconductors increases appreciably if certain types of impurities are added. This addition of impurities is called doping.
Please express your views of this topic Definition of Strain by commenting on blog.
Photovoltaic Solar cell
A device, which converts sunlight directly into electricity, is called a solar cell. The semiconducting material to which a small quantity of a specific impurity is added is called doped semiconductor material. For example, when a small quantity of arsenic is added to ultrapure silicon, the silicon so obtained is termed as doped silicon. The conductivity of such semiconductor materials increases when light falls on them and a potential difference is developed between the two points in the semiconductor material. This cause a flow of a electric current. A single silicon solar cell of about 4 squared centimeter develops a potential difference of about 0.5 volt at 60 milliampere current. Due to this reason the solar cell is also called as photovoltaic cell. A single solar cell produces very small current at a small potential difference. So, in practice, we use a large number of solar cells connected together. This combination of a large number of solar cells is called a solar cell panel. A solar cell panel can provide stronger currents under high potential difference. Photovoltaic solar cells gained much importance in the last few decades due to the following reasons:
(i) The fossil fuels such as coal, petroleum etc are depleting very fastly, whereas the photovoltaic solar cells are renewable sources of energy.
(ii) Combustion of fossil fuels produce high air pollution and leads to green house effect whereas photovoltaic solar cells does not produce any type of pollution.
(iii) It is an energy source that is inexpensive.
(iv) These are used in remote areas very easily.
Is this topic Force Equation hard for you? Watch out for my coming posts.
Uses of Photovoltaic Solar Cells
(i) Photovoltaic solar cells are used in street lighting in rural areas.
(ii) Photovoltaic solar cells are used for operating water pumps for domestic and agricultural purposes.
(iii) Photovoltaic solar cells are used in satellites.
(iv) Photovoltaic solar cells are used to operate TV and other electrical appliances in our daily life.
Transformer Output Voltage
Introduction to transformer output voltage:
A transformer is a device, which can convert high alternating voltage into low alternating voltage and low alternating voltage into high alternating voltage. The transformer is based on the phenomenon of the mutual induction. If the transformer converts, the high alternating voltage into low alternating voltage it is called the step down transformer and if it converts the low alternating voltage into high alternating voltage it is called the step up transformer.I like to share this Formula of Density with you all through my article.
Construction of Transformer output voltage :
A simple transformer consists of the two coils called primary coil and the other is called the secondary coil. In one of the coil the number of turns of thick, insulated copper wire is less as compared to the other. If the primary coil has more number of turns it behaves like a step down transformer and if the secondary coil has more number of turns it behaves like a step up transformer. If the numbers of turns in the primary coil are Np and the number of turns in the secondary coil are Ns. Let the input voltage is Ep and the output voltage is Es. According to the energy conservation, we get
Ep / Np = Es / Ns = k ( K is called the transformation ratio)
Here we get the output voltage Ep = Es Np / Ns
If Ns < Np then the output voltage is more than the input voltage and the transformer is step up.
If Ns > Np then output voltage is less than input voltage and the transformer is step down.
As the voltage is stepped up or stepped down the current is also reduced or increased in the same ratio.
Understanding Force Equation is always challenging for me but thanks to all science help websites to help me out.
Example for the transformer output voltage :
The ratio of the number of turns in the primary and the secondary coil of a step up transformer is 1: 200. It is connected to ac mains of 200 V. Calculate the voltage developed in the secondary coil.
Solution
Here, Np / Ns = 1 / 200, Ep = 200 V
Es / Ep = Ns / Np
Es / 200 = 200 / 1
Es = 40000 Volt.
A transformer is a device, which can convert high alternating voltage into low alternating voltage and low alternating voltage into high alternating voltage. The transformer is based on the phenomenon of the mutual induction. If the transformer converts, the high alternating voltage into low alternating voltage it is called the step down transformer and if it converts the low alternating voltage into high alternating voltage it is called the step up transformer.I like to share this Formula of Density with you all through my article.
Construction of Transformer output voltage :
A simple transformer consists of the two coils called primary coil and the other is called the secondary coil. In one of the coil the number of turns of thick, insulated copper wire is less as compared to the other. If the primary coil has more number of turns it behaves like a step down transformer and if the secondary coil has more number of turns it behaves like a step up transformer. If the numbers of turns in the primary coil are Np and the number of turns in the secondary coil are Ns. Let the input voltage is Ep and the output voltage is Es. According to the energy conservation, we get
Ep / Np = Es / Ns = k ( K is called the transformation ratio)
Here we get the output voltage Ep = Es Np / Ns
If Ns < Np then the output voltage is more than the input voltage and the transformer is step up.
If Ns > Np then output voltage is less than input voltage and the transformer is step down.
As the voltage is stepped up or stepped down the current is also reduced or increased in the same ratio.
Understanding Force Equation is always challenging for me but thanks to all science help websites to help me out.
Example for the transformer output voltage :
The ratio of the number of turns in the primary and the secondary coil of a step up transformer is 1: 200. It is connected to ac mains of 200 V. Calculate the voltage developed in the secondary coil.
Solution
Here, Np / Ns = 1 / 200, Ep = 200 V
Es / Ep = Ns / Np
Es / 200 = 200 / 1
Es = 40000 Volt.
Wave Model of Light
Introduction to wave model of light
Up to the middle of the 17th century, it was believed that light consisted of stream of corpuscles, emitting by the light source and travelled outwards from the source in straight lines. This theory is known as the Newton’s corpuscular theory. However, after 1827, the experiments of Young and Fresnel on interference, and the measurement of the velocity of light in liquids by the Foucault demonstrated phenomena, which could not be correctly explained by corpuscles theory but could be explained by the wave theory of light.
Huygens wave theory of light
In 1678, Huygens proposed the wave theory of light. According to this wave theory, light travels in the form of waves. These waves after emerging from the light source travel in all directions with the velocity of light. As the wave requires the medium to travel, Huygens imagined an all-pervading medium called aluminiferous ether. It was assumed that the hypothetical medium is weightless and can penetrate through matter. It has all properties necessary for the propagation of light waves. Hence, it was assumed that the density of ether is very small and the elasticity is very large. Light waves travel in such a hypothetical medium. When these waves fall upon the retina of the eye, they cause the sensation of sight. Huygens proposed the geometrical construction to explain the propagation of a wave front in the medium and determined the position of the wave front after any interval of time. They are known as the Huygen’s principle.
Conclusion of Huygeng’s wave theory of light
Every particle of the medium situated on the wave front acts as a new wave source from which the fresh waves originate. These waves are called the secondary wavelets.
The secondary wavelets travel in the medium in all directions with the speed of the original wave in the medium.
The envelope of the secondary wavelets in the forward direction at any instant gives the new wave front at that instant.
Up to the middle of the 17th century, it was believed that light consisted of stream of corpuscles, emitting by the light source and travelled outwards from the source in straight lines. This theory is known as the Newton’s corpuscular theory. However, after 1827, the experiments of Young and Fresnel on interference, and the measurement of the velocity of light in liquids by the Foucault demonstrated phenomena, which could not be correctly explained by corpuscles theory but could be explained by the wave theory of light.
Huygens wave theory of light
In 1678, Huygens proposed the wave theory of light. According to this wave theory, light travels in the form of waves. These waves after emerging from the light source travel in all directions with the velocity of light. As the wave requires the medium to travel, Huygens imagined an all-pervading medium called aluminiferous ether. It was assumed that the hypothetical medium is weightless and can penetrate through matter. It has all properties necessary for the propagation of light waves. Hence, it was assumed that the density of ether is very small and the elasticity is very large. Light waves travel in such a hypothetical medium. When these waves fall upon the retina of the eye, they cause the sensation of sight. Huygens proposed the geometrical construction to explain the propagation of a wave front in the medium and determined the position of the wave front after any interval of time. They are known as the Huygen’s principle.
Conclusion of Huygeng’s wave theory of light
Every particle of the medium situated on the wave front acts as a new wave source from which the fresh waves originate. These waves are called the secondary wavelets.
The secondary wavelets travel in the medium in all directions with the speed of the original wave in the medium.
The envelope of the secondary wavelets in the forward direction at any instant gives the new wave front at that instant.
How Big Is The Sun
Introduction on the sun:
Astronomers categorize the sun as a "Yellow G2 Dwarf." It is an average, middle-aged star. Without it there would have been no life on earth though. The life on earth has arisen because of its just the right distance from the sun at just the right moment in sun’s life and in a way we are lucky to be here at the right moment in the eternity of existence of universe.Having problem with Definition of Buoyancy keep reading my upcoming posts, i will try to help you.
Like all stars hydrogen nuclei fuse together to form helium nuclei leading to a burst of energy, heating up and powering the Sun and this atomic reaction makes the Sun lose a tiny amount of its mass continuously. We need not feel concerned though, as there is enough fuel to last a billion years or more.
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Explanation to how big is the sun:
The sun is big, very big. It constitutes 99% of matter in the solar system – remaining 1% being taken up by the planets, comets, asteroids and moons of the solar system. It is equivalent to 330,000 times the mass of our earth. The Sun is about 1,391,980 kilometres (864,938 miles) in diameter. It is difficult to imagine as one can never see anything similar at close quarters. Compare it to our planet Earth, which is just 12,756 kilometres (7,926 miles) wide or let us take the biggest planet in the solar system, Jupiter, which is just 142,600 kilometres (88,700 miles) wide.
We can now see that the Sun is huge, but it is interesting to know that it is tiny in comparison to many other stars. A star called Betelgeuse is 0.5 billion kilometres wide and about 500 times the size of the sun! Stars tend to become bigger as they get older. Our Sun is still young and only about 4.5 billion years old, which is nearly half way through its life. It too will become bigger as it gets older and perhaps "eat up" some of the inner planets, Mercury, Venus, and possibly Earth and Mars too. Life will surely cease to exist on our planet Earth when that happens.
Astronomers categorize the sun as a "Yellow G2 Dwarf." It is an average, middle-aged star. Without it there would have been no life on earth though. The life on earth has arisen because of its just the right distance from the sun at just the right moment in sun’s life and in a way we are lucky to be here at the right moment in the eternity of existence of universe.Having problem with Definition of Buoyancy keep reading my upcoming posts, i will try to help you.
Like all stars hydrogen nuclei fuse together to form helium nuclei leading to a burst of energy, heating up and powering the Sun and this atomic reaction makes the Sun lose a tiny amount of its mass continuously. We need not feel concerned though, as there is enough fuel to last a billion years or more.
Please express your views of this topic Physics Formula Sheet by commenting on blog.
Explanation to how big is the sun:
The sun is big, very big. It constitutes 99% of matter in the solar system – remaining 1% being taken up by the planets, comets, asteroids and moons of the solar system. It is equivalent to 330,000 times the mass of our earth. The Sun is about 1,391,980 kilometres (864,938 miles) in diameter. It is difficult to imagine as one can never see anything similar at close quarters. Compare it to our planet Earth, which is just 12,756 kilometres (7,926 miles) wide or let us take the biggest planet in the solar system, Jupiter, which is just 142,600 kilometres (88,700 miles) wide.
We can now see that the Sun is huge, but it is interesting to know that it is tiny in comparison to many other stars. A star called Betelgeuse is 0.5 billion kilometres wide and about 500 times the size of the sun! Stars tend to become bigger as they get older. Our Sun is still young and only about 4.5 billion years old, which is nearly half way through its life. It too will become bigger as it gets older and perhaps "eat up" some of the inner planets, Mercury, Venus, and possibly Earth and Mars too. Life will surely cease to exist on our planet Earth when that happens.
Sunday, May 26, 2013
Van De Graaff Generator
Introduction to Van de Graaff generator:
Let us learn about the van de Graaff generator. Van de graaff generator produces a continuous supply of charge on a large metal dome when a rubber belt is driven by an electric motor or by hand which is show in the figure. For example pens and combs made of certain plastics become charged when rubbed on your sleeve and can then attract scraps of paper.
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Positive and Negative Charge:
When a strip of polythene is rubbed with a cloth it becomes c harged. If it is hung up ans another rubbed polythene strip is brought near, repulsion occurs. Attraction occurs when a rubbed strip of cellulose acetate approaches.
This shows there are two kinds of electric charge. That on cellulose acetate is taken as positive (+) and that on polythene is negative (-). The force between electric charges decreases as their separation increases.
Demonstrations:
Let us see the demonstration of Van de Graaff generator. In our figure a, sparks jump between the dome and the discharging sphere. Electrons flow round a complete path from the dome. In part b why does the ‘hair’ stand on end? In part c the ‘windmill’ revolves due to the reaction that arises from the ‘electric wind’ caused by the action at points effect, explained above for the lightning conductor.Is this topic Average Speed Formula hard for you? Watch out for my coming posts.
Action:
Let us see the action of Van de Graaff generator. Initially a positive charge is produced on the motor-driven Perspex roller due to it rubbing the belt. This induces a negative charge on the ‘comb’ of metal points P, in figure a, which are sprayed off by ‘action at points’ on to the outside of the belt and carried upwards. A positive charge is then induced in the comb of metal points Q and negative charge is repelled to the dome. This concept will clearly explained you to know about the Van de graaff generator.
Let us learn about the van de Graaff generator. Van de graaff generator produces a continuous supply of charge on a large metal dome when a rubber belt is driven by an electric motor or by hand which is show in the figure. For example pens and combs made of certain plastics become charged when rubbed on your sleeve and can then attract scraps of paper.
Having problem with Specific Heat Capacity of Ice keep reading my upcoming posts, i will try to help you.
Positive and Negative Charge:
When a strip of polythene is rubbed with a cloth it becomes c harged. If it is hung up ans another rubbed polythene strip is brought near, repulsion occurs. Attraction occurs when a rubbed strip of cellulose acetate approaches.
This shows there are two kinds of electric charge. That on cellulose acetate is taken as positive (+) and that on polythene is negative (-). The force between electric charges decreases as their separation increases.
Demonstrations:
Let us see the demonstration of Van de Graaff generator. In our figure a, sparks jump between the dome and the discharging sphere. Electrons flow round a complete path from the dome. In part b why does the ‘hair’ stand on end? In part c the ‘windmill’ revolves due to the reaction that arises from the ‘electric wind’ caused by the action at points effect, explained above for the lightning conductor.Is this topic Average Speed Formula hard for you? Watch out for my coming posts.
Action:
Let us see the action of Van de Graaff generator. Initially a positive charge is produced on the motor-driven Perspex roller due to it rubbing the belt. This induces a negative charge on the ‘comb’ of metal points P, in figure a, which are sprayed off by ‘action at points’ on to the outside of the belt and carried upwards. A positive charge is then induced in the comb of metal points Q and negative charge is repelled to the dome. This concept will clearly explained you to know about the Van de graaff generator.
Pendulum Gravity
Introduction to pendulum gravity:
Galileo achieve the experiment scheduled acceleration suitable to gravity. He illustrate that condition substance are dropped consequently because to fall freely from the similar height they achieve the plane of the earth at the same time supply the resistence obtainable by the air through this method is neglected. This demonstrate to while substance are dropped they occurrence consistent acceleration due to the gravitational magnetism of the earth towards its earth.Is this topic Gravitational Acceleration Formula hard for you? Watch out for my coming posts.
Gravity:
This uniform attraction qualified through an object towards center of the earth is recognized as acceleration due to gravity. It is represented by the g with is definite as the energy experienced through an object having unit mass.
The importance acceleration suitable to gravity varies from place to place, average value is 9.81ms-2. It has a maximum value at the poles and a minimum value at equator.
I have recently faced lot of problem while learning Gravity Formula, But thank to online resources of science which helped me to learn myself easily on net.
Type of pendulum gravity:
Simple pendulum gravity:
A simple pendulum is serious object resembling a bob balanced at one end of an inextensible and weights string. The further end of the string is attached to a rigid support. The point at that the string is attached is identified as point of suspension. A small metallic spherical bob attached to a thread signify a simple pendulum.
that executes harmonic motion, time period is independent of amplitude. The time period of the pendulum, T = 2p`sqrt((1)/(g))`
Where l is the length of the pendulum and g is the acceleration suitable to gravity. The length of the pendulum is measured from the position of deferment to the middle of spherical bob.
Drawback of simple pendulum gravity:
The bob of the simple pendulum is not a point object and the string is not a weights string. The string also has a moment of inertia about the suspension axis. The simple pendulum is not an ideal one.
The motion of the bob is not merely a translation one but it also rotates about the point of suspension.
Compound pendulum gravity:
A compound pendulum is rigid body capable of oscillating freely about a horizontal axis passing through it. A rigid body of any shape and internal structure capable of making oscillation about a horizontal axis constitutes a pendulum.
Galileo achieve the experiment scheduled acceleration suitable to gravity. He illustrate that condition substance are dropped consequently because to fall freely from the similar height they achieve the plane of the earth at the same time supply the resistence obtainable by the air through this method is neglected. This demonstrate to while substance are dropped they occurrence consistent acceleration due to the gravitational magnetism of the earth towards its earth.Is this topic Gravitational Acceleration Formula hard for you? Watch out for my coming posts.
Gravity:
This uniform attraction qualified through an object towards center of the earth is recognized as acceleration due to gravity. It is represented by the g with is definite as the energy experienced through an object having unit mass.
The importance acceleration suitable to gravity varies from place to place, average value is 9.81ms-2. It has a maximum value at the poles and a minimum value at equator.
I have recently faced lot of problem while learning Gravity Formula, But thank to online resources of science which helped me to learn myself easily on net.
Type of pendulum gravity:
Simple pendulum gravity:
A simple pendulum is serious object resembling a bob balanced at one end of an inextensible and weights string. The further end of the string is attached to a rigid support. The point at that the string is attached is identified as point of suspension. A small metallic spherical bob attached to a thread signify a simple pendulum.
that executes harmonic motion, time period is independent of amplitude. The time period of the pendulum, T = 2p`sqrt((1)/(g))`
Where l is the length of the pendulum and g is the acceleration suitable to gravity. The length of the pendulum is measured from the position of deferment to the middle of spherical bob.
Drawback of simple pendulum gravity:
The bob of the simple pendulum is not a point object and the string is not a weights string. The string also has a moment of inertia about the suspension axis. The simple pendulum is not an ideal one.
The motion of the bob is not merely a translation one but it also rotates about the point of suspension.
Compound pendulum gravity:
A compound pendulum is rigid body capable of oscillating freely about a horizontal axis passing through it. A rigid body of any shape and internal structure capable of making oscillation about a horizontal axis constitutes a pendulum.
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