If a body has the ability to exert a influence into the area around that body in space, it has what is defined as a field about its position. That is, for example, a force that is able to create a localized area that the effect of the force can be physically felt, is known as a field force.
The forces in nature that generate a field are electric, magnetic, and gravitational forces.
While the field generated by the force cannot be seen directly with the eye, its effect can be felt, and we can also construct a virtual graph extremely easily.
In other words, we can regard a force field to be like a map of force in an open area, where the effect of the force can be felt.
Most field forces that exist in nature will have a vector field associated with it having a particular direction and magnitude.
For example an electric field is a field that is present around a electric charge. Once a charge or uncharged body comes into a point in space where there is a electric field present, it will feel (most likely) either a force of attraction or a force of repulsion depending upon the charge that it is carried, and the charge field.
A body that has mass has a field generated around itself that is the gravitational field of the force of gravity that the body experiences that provides a pull towards center of the earth.
In the case of the gravitational field has been verified to at most give a force of attraction on matter, and at worst, will yield no force of repulsion.
Examples of Field Forces
1. Weight of an Object
An object’s weight on Earth is simply the amount of gravity acting on it.
Gravitation is a force in nature that can exert itself through a field; therefore, the weight of an object existing on Earth can be determined by measuring the density of the gravitational field acted on by the mass of the object.
2. Magnetic Effect
A ferrous material placed near a magnet gets attracted to the magnet. The intensity of the magnet’s attractive force depends upon the distance between the ferrous material and the magnet.
The magnet’s force of attraction is strongest near the magnet and its strength decreases with distance.
It is this variation in the force of attraction about the surface of the magnet that allows us to plot a map of the magnetic field around it. Therefore, magnetic force is also referred to as a field force.
3. Magnitude of Earth’s Gravity
The sun exerts a gravitational pull on the earth. The value of the gravitational field is related to the diameter of the body. The sun has a gigantic diameter equal to 1.3927 million km.
Because of such a large diameter it can exert a large field force on the objects surrounding it.
However, the orbit of the earth is oval and not a perfect circle, therefore the earth experiences different values of gravitational field throughout the year.
4. Astronauts Floating in Space
When astronauts enter space, they leave the gravitational field behind. They float because there is no force which can bring them back to earth.
The closer one gets to the centre of the earth, the stronger the gravitational force. The farther one moves away from the centre of the earth, the weaker the gravitational force becomes.
The absence of the effect of gravitational force allows an astronaut to float in space.
5. Glass Rod and Pim-pom ball
Charging a piece of glass by rubbing it with a piece of material causes to develop a sizable amount of charge of a certain polarity.
When the charged glass is brought in proximity to a lightweight pim pom ball it will either attract or repel the ball depending on the nature of the charge on each body. The strength of that attraction or repulsion will vary as the distance between them changes.
A map that represents essentially the strength of the field that is created from the electrostatic force is called the electric field. Thus, electrostatic force is an example of one type of field force.
6. Same Poles of Magnets
Magnets have two poles (north and south), plus, a field that surrounds it.
A field line is an imaginary line that starts at the North Pole and ends at the South Pole.
When two magnets are brought close together, one magnetic speaks is interference with the other magnetic field.
The magnets will attract one another when the two fields are in phase (i.e. constructive interference) and they repel when they are out of phase (i.e. destructive interference). Another real-world scenario that shows how a field force operates.
7. TV Interference
Television hardware is full of a number of electronic components connected to each other.
When power is supplied and the current goes through the circuit, the conductors will tend to form a field around themselves due to the potential difference and flowing electric current.
The field formed around the components of the circuitry interfere with each other and create a noise signal. Interference made in this way is made by the field force existing.
8. Comb and Paper Pieces
As a person combs his/her hair a static charge gets created on the comb. The comb generates a field around itself and acts like a charged body in the field. The field acts in a way that exerts a force that can attract or repel an object that comes near it.
For example, bits of paper near a charged comb will stick to the comb when they enter the field, since the field is created by the static electricity.