This lesson note covers Fields in Physics that can help students of the classes of upper sixth or lower sixth. You can as well read this for the purpose of gaining knowledge about the topic.
In this lesson notes, we will cover the different types of fields in physics, their sources, and what they affect.
What is a field in physics?
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In physics, a field is a region in space arround a particle (e.g a mass of charge, nucleon) where another of the same kind will experience a force when placed in it.
Alternatively, it can be defined as is a physical quantity, represented by a number or another tensor, that has a value for each point in space and time. For example, on a weather map, the surface temperature is described by assigning a number to each point on the map; the temperature can be considered at a certain point in time or over some interval of time, to study the dynamics of temperature change[…].
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Types of fields in physics
A field can be classified as a scalar field, a vector field, a spinor field, or a tensor field according to whether the represented physical quantity is a scalar, a vector, a spinor, or a tensor, respectively
Fields are usually grouped into:
- Electric fields
- Magnetic fields
- Gravitational fields
- and Nuclear fileds.
Field type | source of filed | What it affects |
---|---|---|
Electric field | Stationary charges | Charges |
Magnetic field | Moving charges | Moving charges and magnetic materials |
Gravitational field | Masses | Everything in nature |
Nuclear filed | Nucleons | Protons, neutrons, Quartz |
Field theory
In physics, forces can be described by fields that mediate interactions between separate objects. In the mid-19th century, James Clerk Maxwell formulated the first field theory in his theory of electromagnetism.
Albert Einstein later in the 20th century developed general relativity, a field theory of gravitation.
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Field theory usually refers to a construction of the dynamics of a field, that is, a specification of how a field changes with time or with respect to other independent physical variables on which the field depends.
Usually this is done by writing a Lagrangian or a Hamiltonian of the field, and treating it as a classical or quantum mechanical system with an infinite number of degrees of freedom. The resulting field theories are referred to as classical or quantum field theories.
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