One hundred percent of the visible universe completely respond to magnetism. It can either be positive or negative. When we see things from our view, that is from the human point of view. It can be dealing with physical things, physical jobs, eating physical food, grabbing physical things. In short, we are only able to think or do things from the premise of physicality. We only have the ability to think in terms of matter, or what can be quantified.
Then we have the issue that 100% of the universe is filled with fields. Since fields are not particles, they can’t be quantified. They neither have quantity nor quality. But we can certainly define the field with a time variable. That is from the temporal dimension. Maxwell field equation or expressions give interactions, quantifications only over a given period of time. So what are we talking about a field in principle?
Mother nature possess many types of fields; Magnetic field, electric field, gravitational field, etc to name a few. So what is magnetic field? It is a region/field around a magnetic material. It can be also observed around a moving electric charge inside which the force of magnetism works.
We know very well that two magnets put together will either attract or repel each other depending upon the polarity. The magnetic field of the earth is also very strong. Where the North pole and South pole of Earth acts like two poles of magnets and we can draw magnetic field line for understanding purpose.
The characteristic of the magnetic field is used for a plethora of applications. Magnets can be used to rotate metallic plates in the electric motor. The torque needed for a desired angular acceleration about a rotational axis is achieved by supplying current to the pair of magnets. When the polarity of alternating current changes, magnets attract and repel. This makes the metallic plate spin rapidly.
The amount of torque necessary for desired angular acceleration about a fixed rotational axis is defined as the moment of inertia and is measured using the moment of inertia units.
Thus, we got a brief insight into how the entire universe is filled with various fields especially, magnetic field and how we can use it for multiple days to day applications like an electric motor.
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