Back to: PHYSICS SS1
Welcome to class!
In today’s class, we will be talking about the field. Enjoy the class!
Field
The field is described as a region of space under the influence of some physical agency such as gravitational, magnetism and electricity. The field concept is a convenient and informative method of describing the influence of one body over another body separated from the first by some distance.
Force field
A force field is defined as the force whose sources do not require contact with the body to which they are applied. We identified such force field as a gravitational force field, electric force, magnetic force and electromagnetic force.
Types of force field
There are two classes of force fields:
- Scalar force filed
- Vector force field
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Scalar force field:
A scalar force field is one that has only magnitude but no direction, e.g. Temperature, energy and density.
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Vector force field:
A vector force filed is the one that has both magnitude and direction, e.g. gravitational, magnetic and electric fields.
Type of field
- Gravitational Field
- Magnetic Field
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Gravitational field:
A gravitational field is a force field that affects every object that has mass. The earth’s gravitational field attracts every object in the earth and gives it an acceleration known as acceleration due to gravity. It is represented by the symbol g whose average value is about 9.81m/s2.
The Force of gravitational attraction is given by:
F = mg,
Where g is the acceleration due to gravity and m is the mass of the object.
Newton’s law of universal gravitation
Newton’s laws of universal gravitation are used to explain the gravitational force. This law states that every massive particle in the universe attracts every massive particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This general, physical law was derived from observations made by induction. Another way, more modern, way to state the law is every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between the point masses.
Magnetic field
The region or space around a magnet in which the influence of the magnetic can be felt or detected is called the magnetic field.
This space can be mapped out using a magnetic needle. The compass needle when placed in a magnetic field, swings around and settles in a definite direction. The swinging of the needle when in the vicinity of the magnet shows that it has been subjected to a force. This force is known as the magnetic force. Thus magnetic field is a force field. Magnetic force can be felt at a distance. It influences an object even when not in contact with it.
A magnetic field is also a vector field, i.e. it has both magnitude and direction.
We can demonstrate the pattern or nature of the magnetic field around a bar magnet by use of:
- Iron filings
- Magnetic compass
In our next class, we will be talking about Electric Field. We hope you enjoyed the class.
Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.
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