Part 4 of 6 part Series of Understanding the Universe :-
Equation 4: - F = (K. Q1.Q2)/R^2
In 1752, so the story goes, Benjamin Franklin flew a kite in a thunderstorm. The most likely outcome of such an experiment is that you would get yourself killed, so there is some debate as to whether it actually occurred. We do know that similar experiments with lightning rods did occur. What Franklin and others were trying to do is to show that lightning was a kind of electricity.
By the mid-1700s, we had a basic understanding of electricity. We knew that there were two types of charge (positive and negative) and that charge could be transferred between objects. Similar charge repels each other & opposite charges attracts each other.
Then in 1785 Charles Augustin de Coulomb published a work on charge that included the equation shown above. This equation is now known as Coulomb’s law. In this equation F is the force between two objects, the Qs are the charges of those objects, R is the distance between them, and K is a constant known as Coulomb’s constant.
If you remember Part 2 on Newton’s gravity (https://www.facebook.com/photo.php?fbid=290154581116435&set=a.173415186123709.39828.100003656865563&type=1), you might think this equation looks familiar, and you could be right. Like gravity, charged objects have a mutual force between them. This force is stronger when they are close together, and weaker when far apart. The force between charges is, in fact, exactly the same as the force of gravity except for one key difference. Gravity is always an attractive force but where as this force could be positive or -ve depending on charges.
This similarity between Coulomb’s equations and Newton’s led some scientists to think if there was a deeper connection between things like charge and mass. It also drove some scientists to search for a similar equation describing magnetism.
In many ways magnets are very similar to charges. Magnets have two poles(north and south).
Like charges, similar poles push away from each other, while opposite poles attract. You could also magnetize certain materials like iron by rubbing it against a magnet.
In particular, if you break a magnet in half, you don’t get a separate north pole and south pole, you instead get two smaller magnets, each with their own north and south pole.Charges could be separated into positives and negatives, but magnets always came in north-south pairs. that means we can have electric monopole (either positive charge or negative charge) but magnetic monopole does not exist.This was a big mystery. Magnets and charges seemed so similar, and yet they didn’t seem to be connected.
By the early 1800s, electricity could be controlled & Charges could be made to move through metal wires, creating a flow of electricity called a current. In 1819, Hans Christian Oersted accidentally move a compass near one of his wires having current flowing through it, and he noticed that an electric current deflected the compass.
it seems that flowing current produces magnetic field.
In 1831 Michael Faraday demonstrated that moving a wire near a magnet could create an electric current in the wire. or moving the magnet near the wire producess current in the wire. Electricity and magnetism were connected. Electric currents could create magnets, and magnets could create electric currents.
Then in the 1860s James Clerk Maxwell started to work and published a set of elegant and beautifully equations, of which the equation above is just the first. & all these equations are now called Maxwell’s equations.
it just describes the force between two charges. But how does one charge pushes or pulled by the other charge? How do they interact across the empty space between them. Maxwell’s idea was that each charge must reach out to each other with some kind of energy. That is, a charge is surrounded by a field of electricity, a field that other charges can detect. Charges possess electric fields, and charges interact with the electric fields of other charges. The same must be true of magnets. Magnets possess magnetic fields, and interact with magnetic fields. Maxwell found the connection between electricity and magnetism.
They were connected by their fields. A moving electric field creates a magnetic field, and a moving magnetic field creates an electric field. Maxwell had created a single, unified description of electricity and magnetism. He had united two different forces into a single unified force, which we now call electromagnetism.
Maxwell’s theory had another interesting consequence. Since a moving electric field could produce a magnetic field, and a moving magnetic field could produce an electric field, it was possible for an electric field to produce a magnetic field which in turn produce an electric field. Back and forth, over and over, creating a continuing wave of electric and magnetic fields. Maxwell calculated the speed of such a wave. It was exactly the speed of light. In combining electricity and magnetism, Maxwell proved that light is an electromagnetic wave.
Maxwell’s equations are still central to modern astronomy. We now observe a wide range electromagnetic waves from visible light, to radio waves to x-rays. These waves interact with magnets and charges, and those interactions tell us about the universe.
But the equation above is important for another reason as well. Coulomb’s equation was the first of what became Maxwell’s unified theory of charges, magnets and light.
Over the years we have discovered other unified theories.
The unified theories helps us to understand the earliest moments of the big bang, and the workings of black holes. but there are still many cosmic mysteries where we don’t yet know the connections. How does quantum mechanics connect to gravity? Is dark energy a separate field, or is it connected to the fields we know? So we continue to search for deeper and more connections, hoping to find a single description of all the forces and fields and particles in the universe.
Equation 4: - F = (K. Q1.Q2)/R^2
In 1752, so the story goes, Benjamin Franklin flew a kite in a thunderstorm. The most likely outcome of such an experiment is that you would get yourself killed, so there is some debate as to whether it actually occurred. We do know that similar experiments with lightning rods did occur. What Franklin and others were trying to do is to show that lightning was a kind of electricity.
By the mid-1700s, we had a basic understanding of electricity. We knew that there were two types of charge (positive and negative) and that charge could be transferred between objects. Similar charge repels each other & opposite charges attracts each other.
Then in 1785 Charles Augustin de Coulomb published a work on charge that included the equation shown above. This equation is now known as Coulomb’s law. In this equation F is the force between two objects, the Qs are the charges of those objects, R is the distance between them, and K is a constant known as Coulomb’s constant.
If you remember Part 2 on Newton’s gravity (https://www.facebook.com/photo.php?fbid=290154581116435&set=a.173415186123709.39828.100003656865563&type=1), you might think this equation looks familiar, and you could be right. Like gravity, charged objects have a mutual force between them. This force is stronger when they are close together, and weaker when far apart. The force between charges is, in fact, exactly the same as the force of gravity except for one key difference. Gravity is always an attractive force but where as this force could be positive or -ve depending on charges.
This similarity between Coulomb’s equations and Newton’s led some scientists to think if there was a deeper connection between things like charge and mass. It also drove some scientists to search for a similar equation describing magnetism.
In many ways magnets are very similar to charges. Magnets have two poles(north and south).
Like charges, similar poles push away from each other, while opposite poles attract. You could also magnetize certain materials like iron by rubbing it against a magnet.
In particular, if you break a magnet in half, you don’t get a separate north pole and south pole, you instead get two smaller magnets, each with their own north and south pole.Charges could be separated into positives and negatives, but magnets always came in north-south pairs. that means we can have electric monopole (either positive charge or negative charge) but magnetic monopole does not exist.This was a big mystery. Magnets and charges seemed so similar, and yet they didn’t seem to be connected.
By the early 1800s, electricity could be controlled & Charges could be made to move through metal wires, creating a flow of electricity called a current. In 1819, Hans Christian Oersted accidentally move a compass near one of his wires having current flowing through it, and he noticed that an electric current deflected the compass.
it seems that flowing current produces magnetic field.
In 1831 Michael Faraday demonstrated that moving a wire near a magnet could create an electric current in the wire. or moving the magnet near the wire producess current in the wire. Electricity and magnetism were connected. Electric currents could create magnets, and magnets could create electric currents.
Then in the 1860s James Clerk Maxwell started to work and published a set of elegant and beautifully equations, of which the equation above is just the first. & all these equations are now called Maxwell’s equations.
it just describes the force between two charges. But how does one charge pushes or pulled by the other charge? How do they interact across the empty space between them. Maxwell’s idea was that each charge must reach out to each other with some kind of energy. That is, a charge is surrounded by a field of electricity, a field that other charges can detect. Charges possess electric fields, and charges interact with the electric fields of other charges. The same must be true of magnets. Magnets possess magnetic fields, and interact with magnetic fields. Maxwell found the connection between electricity and magnetism.
They were connected by their fields. A moving electric field creates a magnetic field, and a moving magnetic field creates an electric field. Maxwell had created a single, unified description of electricity and magnetism. He had united two different forces into a single unified force, which we now call electromagnetism.
Maxwell’s theory had another interesting consequence. Since a moving electric field could produce a magnetic field, and a moving magnetic field could produce an electric field, it was possible for an electric field to produce a magnetic field which in turn produce an electric field. Back and forth, over and over, creating a continuing wave of electric and magnetic fields. Maxwell calculated the speed of such a wave. It was exactly the speed of light. In combining electricity and magnetism, Maxwell proved that light is an electromagnetic wave.
Maxwell’s equations are still central to modern astronomy. We now observe a wide range electromagnetic waves from visible light, to radio waves to x-rays. These waves interact with magnets and charges, and those interactions tell us about the universe.
But the equation above is important for another reason as well. Coulomb’s equation was the first of what became Maxwell’s unified theory of charges, magnets and light.
Over the years we have discovered other unified theories.
The unified theories helps us to understand the earliest moments of the big bang, and the workings of black holes. but there are still many cosmic mysteries where we don’t yet know the connections. How does quantum mechanics connect to gravity? Is dark energy a separate field, or is it connected to the fields we know? So we continue to search for deeper and more connections, hoping to find a single description of all the forces and fields and particles in the universe.
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