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INTRODUCTION TOLoading...
CHARGESLoading...
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VARSHA PATIL
Introduction
Charges
Have you ever wondered? Why a balloon after rubbing with your clothes easily clings to the wall or how a comb after rubbing with your hair attracts those small bits of paper or What is a lightning strike?
All these phenomena can be explained by understanding the concept of electric charges.
All these phenomena can be explained by understanding the concept of electric charges.
Few centuries ago, it was discovered that when glass rod is rubbed with silk cloth, they attracted each other as well as lighter objects like straw and bits of paper. Later we found many such pair of materials existed which exhibit this kind of behavior. It took around 2000 years for the first successful explanation for this phenomenon.
Benjamin Franklin
Lightning is caused due to charge discharge in the atmosphere when air gets ionized, due to high potential difference between earth surface and clouds.
When we take two glass rods and rub it with silk cloth, we see they repel each other. Similarly, when two silk cloths are rubbed with a glass rod, they repel each other. But, if we bring the glass rod close to silk cloth after rubbing them with each other, they attract each other... strange! isn’t it?
To explain this strange behavior, Benjamin Franklin proposed that, when we rub two different objects with each other, there might be a transfer of a transparent fluid between them. Now did he see this fluid? No.. that is why he called it transparent because one cannot see it and fluid is anything which flows. So what he meant was something flows between glass rod and silk cloth when you rub it with each other. So after the objects are rubbed with each other, one of them has excess fluid and the other has less fluid than normal. This fluid in those days was called as Charge, and the objects were called charged or electrified bodies.
To explain this strange behavior, Benjamin Franklin proposed that, when we rub two different objects with each other, there might be a transfer of a transparent fluid between them. Now did he see this fluid? No.. that is why he called it transparent because one cannot see it and fluid is anything which flows. So what he meant was something flows between glass rod and silk cloth when you rub it with each other. So after the objects are rubbed with each other, one of them has excess fluid and the other has less fluid than normal. This fluid in those days was called as Charge, and the objects were called charged or electrified bodies.
Introduction
Charges
Have you ever wondered? Why a balloon after rubbing with your clothes easily clings to the wall or how a comb after rubbing with your hair attracts those small bits of paper or What is a lightning strike?
All these phenomena can be explained by understanding the concept of electric charges.
All these phenomena can be explained by understanding the concept of electric charges.
Few centuries ago, it was discovered that when glass rod is rubbed with silk cloth, they attracted each other as well as lighter objects like straw and bits of paper. Later we found many such pair of materials existed which exhibit this kind of behavior. It took around 2000 years for the first successful explanation for this phenomenon.
Benjamin Franklin
Lightning is caused due to charge discharge in the atmosphere when air gets ionized, due to high potential difference between earth surface and clouds.
When we take two glass rods and rub it with silk cloth, we see they repel each other. Similarly, when two silk cloths are rubbed with a glass rod, they repel each other. But, if we bring the glass rod close to silk cloth after rubbing them with each other, they attract each other... strange! isn’t it?
To explain this strange behavior, Benjamin Franklin proposed that, when we rub two different objects with each other, there might be a transfer of a transparent fluid between them. Now did he see this fluid? No.. that is why he called it transparent because one cannot see it and fluid is anything which flows. So what he meant was something flows between glass rod and silk cloth when you rub it with each other. So after the objects are rubbed with each other, one of them has excess fluid and the other has less fluid than normal. This fluid in those days was called as Charge, and the objects were called charged or electrified bodies.
To explain this strange behavior, Benjamin Franklin proposed that, when we rub two different objects with each other, there might be a transfer of a transparent fluid between them. Now did he see this fluid? No.. that is why he called it transparent because one cannot see it and fluid is anything which flows. So what he meant was something flows between glass rod and silk cloth when you rub it with each other. So after the objects are rubbed with each other, one of them has excess fluid and the other has less fluid than normal. This fluid in those days was called as Charge, and the objects were called charged or electrified bodies.
Video Demonstration: Like charges repel each other and unlike charges attract each other. Credit: MIT
He randomly called the body with excess fluid as positively charged and the one with less fluid as negatively charged and he “assumed” that this fluid flows from silk to glass, therefore, glass has excess fluid so he called it positive and silk has less fluid so he called it negative.
He then stated that like charges repel each other and unlike charges attract each other which was found to be experimentally true with many different materials and so far we believe that there exist only two kinds of charges because all the experiments agree with Franklins' fluid theory.
He then stated that like charges repel each other and unlike charges attract each other which was found to be experimentally true with many different materials and so far we believe that there exist only two kinds of charges because all the experiments agree with Franklins' fluid theory.
In our example, of glass and silk, it was practically found that tiny bits of matter called electrons are transferred from glass to silk, because silk has a stronger attraction towards electron than glass. Note that this is opposite to fluid flow assumed by Franklin which was from silk to glass. And, now since glass rod was called positively charged and silk was called negatively charged by Franklin, in his honor, we call electrons as negatively charged so rubbing glass and silk together transfers negatively charged electron to silk and therefore, silk is negative and glass is positive.
Now lets us take our understanding of charges to atomic level and see what is going on inside. We know that every matter in the universe is made up of atoms, and every atom consists of protons, neutrons and electrons. Protons and neutrons together constitute the nucleus of the atom; the negatively charged electrons revolve around the nucleus in different orbits and since protons attract electrons, protons are called as positively charged and neutrons do not attract or repel electron, therefore, they are neutral.
It was also found that electrons and protons carry the same fundamental charge but opposite in nature which we denote by ‘e’ and it has a value of 1.6 x 10^-19C.
Since an atom contains equal number of protons and electrons, the atom as the whole, is electrically neutral. Now, what happens if an electron is removed from the outermost orbit of the atom?
Now lets us take our understanding of charges to atomic level and see what is going on inside. We know that every matter in the universe is made up of atoms, and every atom consists of protons, neutrons and electrons. Protons and neutrons together constitute the nucleus of the atom; the negatively charged electrons revolve around the nucleus in different orbits and since protons attract electrons, protons are called as positively charged and neutrons do not attract or repel electron, therefore, they are neutral.
It was also found that electrons and protons carry the same fundamental charge but opposite in nature which we denote by ‘e’ and it has a value of 1.6 x 10^-19C.
Since an atom contains equal number of protons and electrons, the atom as the whole, is electrically neutral. Now, what happens if an electron is removed from the outermost orbit of the atom?
Video Demonstration: Like charges repel each other and unlike charges attract each other. Credit: MIT
He randomly called the body with excess fluid as positively charged and the one with less fluid as negatively charged and he “assumed” that this fluid flows from silk to glass, therefore, glass has excess fluid so he called it positive and silk has less fluid so he called it negative.
He then stated that like charges repel each other and unlike charges attract each other which was found to be experimentally true with many different materials and so far we believe that there exist only two kinds of charges because all the experiments agree with Franklins' fluid theory.
He then stated that like charges repel each other and unlike charges attract each other which was found to be experimentally true with many different materials and so far we believe that there exist only two kinds of charges because all the experiments agree with Franklins' fluid theory.
In our example, of glass and silk, it was practically found that tiny bits of matter called electrons are transferred from glass to silk, because silk has a stronger attraction towards electron than glass. Note that this is opposite to fluid flow assumed by Franklin which was from silk to glass. And, now since glass rod was called positively charged and silk was called negatively charged by Franklin, in his honor, we call electrons as negatively charged so rubbing glass and silk together transfers negatively charged electron to silk and therefore, silk is negative and glass is positive.
Now lets us take our understanding of charges to atomic level and see what is going on inside. We know that every matter in the universe is made up of atoms, and every atom consists of protons, neutrons and electrons. Protons and neutrons together constitute the nucleus of the atom; the negatively charged electrons revolve around the nucleus in different orbits and since protons attract electrons, protons are called as positively charged and neutrons do not attract or repel electron, therefore, they are neutral.
It was also found that electrons and protons carry the same fundamental charge but opposite in nature which we denote by ‘e’ and it has a value of 1.6 x 10^-19C.
Since an atom contains equal number of protons and electrons, the atom as the whole, is electrically neutral. Now, what happens if an electron is removed from the outermost orbit of the atom?
Now lets us take our understanding of charges to atomic level and see what is going on inside. We know that every matter in the universe is made up of atoms, and every atom consists of protons, neutrons and electrons. Protons and neutrons together constitute the nucleus of the atom; the negatively charged electrons revolve around the nucleus in different orbits and since protons attract electrons, protons are called as positively charged and neutrons do not attract or repel electron, therefore, they are neutral.
It was also found that electrons and protons carry the same fundamental charge but opposite in nature which we denote by ‘e’ and it has a value of 1.6 x 10^-19C.
Since an atom contains equal number of protons and electrons, the atom as the whole, is electrically neutral. Now, what happens if an electron is removed from the outermost orbit of the atom?
The mass of the atom reduces by one electron and now there are fewer numbers of electrons than protons in the atom, the atom acquires a positive charge.
But if we add 1 electron to the outermost orbit of an atom, its mass increases by 1 electron and as the number of electrons is more than the number of protons, the atom attains a negative charge, this is how atoms are charged at atomic level.
Students kindly note that, electrons are fundamental particles and we cannot divide them. It means we cannot divide one electron into two or more parts. And as of now, we have not found any other smaller unit of charge. What does this mean?
But if we add 1 electron to the outermost orbit of an atom, its mass increases by 1 electron and as the number of electrons is more than the number of protons, the atom attains a negative charge, this is how atoms are charged at atomic level.
Students kindly note that, electrons are fundamental particles and we cannot divide them. It means we cannot divide one electron into two or more parts. And as of now, we have not found any other smaller unit of charge. What does this mean?
If I have to charge a body to a certain amount, say Q, I have to either add or remove an electron from the body, which means, if I remove one electron i.e I remove -1.6 x 10^-19C from a body. The body now has a positive charge of 1.6 x 10^-19 C, right? And what if I remove one more, the body has a charge of 3.2 x 10^-19C.
So now take a moment and think about this? Is it possible to have a charge of 2.4 x 10^-19C on the body? If so, How many electrons should I remove from the body? Well if your answer is 1.5 electrons, that’s not possible because you cannot divide an electron, i.e we cannot take fractions of electron, like 1.5, 2.3, etc. we can only remove or add integer number of electrons like 1e, 2e, 3e …so on from a body.
Therefore, we can conclude that any amount of charge on a body is an integral multiple of charge of an electron. This concept is called quantization of charge or we say that charge is quantized. The word quantized means that charge can have only certain discrete values and it cannot have any random value. i.e q = ne, where n is an integer.
One must also keep in mind that we deal with charges like 10^-6C , in day to day life, which is extremely bigger than charge on an electron, therefore quantization of charge has little significance in daily life.
So now take a moment and think about this? Is it possible to have a charge of 2.4 x 10^-19C on the body? If so, How many electrons should I remove from the body? Well if your answer is 1.5 electrons, that’s not possible because you cannot divide an electron, i.e we cannot take fractions of electron, like 1.5, 2.3, etc. we can only remove or add integer number of electrons like 1e, 2e, 3e …so on from a body.
Therefore, we can conclude that any amount of charge on a body is an integral multiple of charge of an electron. This concept is called quantization of charge or we say that charge is quantized. The word quantized means that charge can have only certain discrete values and it cannot have any random value. i.e q = ne, where n is an integer.
One must also keep in mind that we deal with charges like 10^-6C , in day to day life, which is extremely bigger than charge on an electron, therefore quantization of charge has little significance in daily life.