If a body is able to exert an influence into the space around itself, it is said to possess a field about its position. This means that a force that is able to create a confined area where the effect of that particular force can be felt is known as a field force. Electric, magnetic, and gravitational force are the forces in nature that are capable of developing a field. The field generated by the force cannot be directly seen by naked eyes but its effect can be felt and a virtual graph can be drawn easily. In other words, a force field can be considered as a map of the force in an open area where the effect of the force can be experienced. Most field forces existing in nature possess a vector field that has a particular magnitude as well as a direction. For example, an electric field is a field present around an electric charge. On bringing a charged or an uncharged body in a location where an electric field is known to be present, the secondary body is much likely to experience a force of attraction or repulsion depending on the nature of the charge present on the body and the field. Similarly, a body possessing mass is subjected to a field around itself that tends to pull it towards the center of the earth. This field is nothing but the gravitational field offered by the force of gravity present on the earth. It has been experimentally verified that the field developed due to the force of gravity only exerts a force of attraction on the matter and not the force of repulsion.
Examples of Field Forces
1. Weight of an Object
The weight of an object present on the earth is nothing but the magnitude of the force of gravity acting on it. Gravitational force is a field force in nature therefore, the weight of an object existing on the earth can be calculated by measuring the intensity of the gravitational field acting on the body’s mass.
2. Magnetic Effect
A ferrous material kept near a magnet gets attracted towards it. The intensity of this force of attraction depends on the distance between the material and the magnet. It is the strongest at the points present near the magnet and is weakest at the points located far away. This variation in the strength of the force of attraction about the surface of the magnet enables us to draw a map of the magnetic field present around it. Hence, the magnetic force is called a field force.
3. Magnitude of Earth’s Gravity
The sun exerts a certain amount of gravitational pull on the earth. The value of the gravitational field is proportional to the diameter of the body. Sun is a huge heavenly body with a diameter equal to 1.3927 million km. The diameter is huge therefore, it is able to exert a great amount of field force on the objects present around it. However, the orbit of the earth is oval and not a perfect circle. This is the reason why earth experiences a different amount of gravitational field throughout the year.
4. Astronauts Floating in Air
Astronauts do not experience gravity, which is why they tend to float in empty space. As a person moves away from the center of the earth, he tends to lose the effect of the earth’s gravitational force because the field becomes comparatively weaker in the places that are located far from the center of the body. The minimized effect of the gravitational field on the body helps an astronaut to float.
5. Glass Rod and Pim-pom ball
When a glass rod is rubbed with a piece of fabric, it tends to develop a significant amount of charge with a dedicated polarity. If this charged glass rod is moved near a light weighed pim-pom ball, it tends to attract or repel the ball depending on the nature of the charges contained by both the bodies. The intensity of the force of attraction or repulsion varies from position to position. A map that shows the strength of the field developed due to the electrostatic force is known as the electric field. Hence, the electrostatic force is a prominent example of a field force.
6. Same Poles of Magnets
A piece of magnet consists of two poles namely, a north pole and a south pole. Every magnet is known to exhibit a field around itself. The field lines are the imaginary lines that, in the case of a magnet, originate from the North Pole and terminate at the South Pole. When two such magnets are brought close, the magnetic field of one magnet interferes with the field of the other. Under constructive interference, the magnets get attracted to each other. Whereas, in case of destructive interference, they repel each other. This is yet another real-life example that displays the action of a field force.
7. TV Interference
Television hardware consists of a large number of electronic components linked to each other. When the power is turned on and the current is made to pass through the circuit, the conductors tend to form a field around themselves due to the existing potential difference and the flowing electric current. The field formed around the components of the circuitry interfere with each other and form a noise signal. Hence, interference is a result of the existing field force.
8. Comb and Paper Pieces
When a person combs his/her hair a certain amount of charge gets developed on the comb. The comb acting as a charged body develops a field around itself that tends to exert a force of attraction or repulsion on the objects present nearby. For instance, bits of paper present near a charged comb tend to get stick to it as soon as they enter the field generated by the static electricity.