This means that these three values cannot be independent; If you know two, you can derive the third. How do physicists manage this? We define the speed of light as exactly 299,792,458 meters for the second. (How do we know that it is exact? Because we define a Metter as the distance light moves in 1 / 299.792 458 of a second.) Then we measure the magnetic constant (μ0) and use this value with the speed of light to calculate the electric constant (ε0).
Maybe it looks like cheating, but even to start doing real science, at some point, we must invent arbitrary units and define certain parameters. In fact, when you wish, all the measurement systems are composed, just like all words are invented.
Permeability of free spaces
Magnetic fields (represented by the symbol B) Can be created by magnets, as indicated in the photo at the top. But because of this interdependence that we are talking about, they can also be made by moving the electrical charges. (I use the “charges” of the term stenography for loaded particles, such as electrons.) This is described by bivi-savart law:
You can see the magnetic constant (μ0) in there. We also have the value of the electrical load (q) Moving with a certain speed (V). So this is sad the Incasse magnetic field with the electric load and decreases with the distance (R) From the moving load – and the magnetic constant tells us precise how much it goes.
Of course, we do not deal very often with individual moving electrons. But we treat moving electricity flows all the time: it is the electric current, which we can measure. If we know the load on the particles in the Coulombs, then the number of coulombs flowing for the second gives us the current (THE) in amps. And we can write the above equation in terms of current: B = μ0I / (2πr).
It’s everywhere
What it tells us is that The electric current generates in the magnetic field. This is used in all kinds of machines. For example, it gives us electrodiments, where magnetic force can be activated and deactivated to move metal objects in factories and landons. This is also how the audio speakers create a sound: an electrical signal vibrates a magnetic pilot, which generates pressure waves in the air.
Alla Magnetic fields influence electric currents. This is how the engines work. There is a current that crosses a coil of wire in the presence of a magnetic field created by Uselly with permanent magnets. The strength on the wire coil runs it and there is your engine. It can be a fan engine, part of your AC compressor or the main drive of an electric car.
Wait! There is more. Just like a changing electric field creates a magnetic field, A changing magnetic field creates an electric field– And this produces an electric current. This is how most of our power is generated. A certain source of energy – team, wind, mobile water, whatever – aspires a turbine that turns a coil with a magnetic field. The changing magnetic flow induces the coil voltage, converting mechanical energy into electrical energy which can be transmitted to your home.
Measure the magnetic constant
How can we measure μ0? A method uses what is called in the current balance. A simple version of it has two parallel wires carrying an electric current (THE) In opposite directions, as indicated in the diagram below. Then you suspend the two wires with strings so that they can separate, like this:
The current in each wire creates a magnetic field at the location of the other wire, which separates them. As they move away, the magnetic force decreases and the horizontal component of the tension in the Incasses of support rope (due to the change of angle). Once these two forces are equal, the sons will be “balanced”.
If you know the value of the electric current and the Bethaeen distance the wires (R), you can determine the magnetic constant, μ0. Then, as we have shown, you can use this value with the defined light speed to calculate the electric constant, ε0.
So yes, overall, you could say that the magnetic constant is quite important. Oh, and what is this constant value? According to the International Committee for Weights and Measures, μ0 = 1.256637061272 × 10–6 N / A2. No more no less.
