24.0.0: DESCRIPTION OF FIELD:
Field is a region as space within which the influence of an agent is field. Field is a vector quantity. It has magnitude and direction.
TYPES OF FIELD:
Field can be classified into scalar field and vector field.
SCALAR FIELD:
A scalar field is the type of field that has only magnitude and no direction. The direction of a scalar field can not determined or known.
EXAMPLE OF SCALAR FIELD:
The following are examples of scalar field:
VECTOR FIELD:
A vector field is the type of field that has both magnitude and direction. The magnitude and direction of the field can be determined by either measurement or calculation using appropriate formulae.
EXAMPLES OF VECTOR FIELD:
1. GRAVITATIONAL FIELD:
Gravitational field is the region or space within which the influence of the force of gravity is felt. In gravitational field, work is done against the force of gravity. It act over a distance. It acts around every object that has mass. It is a force field. It influences the motion of object in the space where it operates.
GRAVITATIONAL ATTRACTION:
It is the earth’s attraction on every object that exit in its gravitational field. The effect of gravitational attraction is to change the velocity of object under its influence. That is to accelerate the object.
PROPERTIES OF A FIELD:
A field may be a scalar field or a vector field
The magnitude of a field can be determined by measurement or calculation
Some Field has directions
ACCELERATION DUE TO GRAVITY:
Acceleration due to gravity is the constant downward velocity of an object per second. It can also be defined as the acceleration of an object under the influence of gravity whose velocity per second is 9.8 m/s.
VALUE OF ACCELERATION DUE TO GRAVITY:
The value of acceleration due to gravity is 9.8 m/s². It is uniform in a given place and the same for all types of bodies irrespective of their masses. However, the value of acceleration due to gravity varies from place to place. It is minimum at the equator ( 9.78 m/s²) and increases with increase in latitude to reach a maximum value of 9.83m/s² at the pole of the earth.
ACCELERATION OF DIFFERENT OBJECTS RELEASED FROM THE SAME HEIGH IN A VACUUM:
When different objects of different masses are released from the same height in a vacuum, the objects fall to the ground at the same time because the same amount of acceleration due to gravity act on them all irrespective of their masses.
In the practical sense, When a stone and a feather are dropped from the same height at the same time, the stone fall faster and faster until it reaches the ground ahead of the feather. The feather falls slowly due to air friction or resistance which reduces the motion of the feather than that of the stone. Also, due to the large surface area of the feather , the feather falls more slowly than the stone.
FORCE OF GRAVITATIONAL ATTRACTION:
The force of gravitational attraction is the product of the mass of the object and the acceleration due to gravity that act on the object. It is given by the formula, force = mass * acceleration due to gravity
Force = mass * acceleration due to gravity.
Force = m*g
ACCELERATION OF FREE FALL DUE TO GRAVITY:
Acceleration of free fall due to gravity is the force of attraction on a unit mass or one kilogram mass of object.
When mass = 1kg, then force = mg = 1* g = g. Force = acceleration due to gravity. F = g
2.MAGNETIC FIELD:
Magnetic field is the region or space around a magnet within which the influence or force of a magnet is felt by a magnetic substance or a magnet. It is a vector field.
MAGNETS:
Magnets are substances that attract magnetic substances.
MAGNETIC SUBSTANCE:
Magnetic substance is a substance that can be attracted by a magnet.
EXAMPLES OF MAGNETIC SUBSTANCES:
The followings are magnetic substances:
MAGNETISM:
Magnetism is the ability of a magnet to attract magnetic substance. The magnetism of a magnet is concentrated at the poles of the magnet.
POLES OF A MAGNET:
Poles of a magnet is the ends of a magnet where the magnetic attraction or the magnetism of the magnet is concentrated.
POSITION OF A FREELY SUSPENDED MAGNET:
When a bar magnet is suspended freely by means of a rope about its centre, the magnet come to rest with its axis pointing approximately in the north – south direction. The end of the magnet that point in the northward direction is the north pole while the other end that point approximately in the southward direction is the south pole.
LAW OF MAGNET:
The law of magnetism States that like poles of magnets repel each other while the unlike poles attract each other.
MAGNETIC FIELD PATTERN OF A BAR MAGNET:
Magnetic field pattern of a bar magnet is the shape or direction of the magnetic line of force of a magnetic as it travels from the north pole of the magnet to the south pole of the magnet.
HOW TO PLOT MAGNETIC FIELD PATTERN OF A BAR MAGNET:
The magnetic field pattern of a magnet can be plotted in two ways :
With or using iron filling
Using a compass needle
PLOTTING MAGNETIC FIELD PATTERN USING IRON FILLINGS:
A thin sheet of glass is placed over a magnet and some quantity of iron fillings are sprinkled on the glass. The iron fillings arranged themselves in a clear and definite pattern on the glass. This pattern is the pattern of the magnetic field of the magnet.
PLOTTING MAGNETIC FIELD PATTERN USING COMPASS NEEDLES:
Place a sheet of paper on a drawing board. Place a bar magnet at the centre of the paper. Place three compass needles at the sides the magnet. The needles of the. Impasses swing and settle in the same directions. Mark n and s of each compass needles to represent the north and south poles of the compass needles. Join the nn and s together to get the magnetic field pattern of the bar magnet.
DIAGRAM:
DIRECTION OF A LINE OF FORCE AT ANY POINT:
It is a direction in which a free North pole that is placed at that point would try to move or follow
EXERCISES:
ELECTRIC FIELD:
Electric field is the region or space around a charge object within which the influence or force of electric charge is felt by another charged body.
It is a way of describing the action of one charge on another charge, from a distance.
ELECTRIC LINE OF FORCE:
Electric line of force is an imaginary line that is drawn in an electric field in such a way that the direction at any point indicate the direction of the electric field at that point.
Electric line of force can also be defined as the path which an isolated small positive charge would follow if placed in the field.
DIRECTION OF AN ELECTRIC FIELD:
The direction of an electric field is given or indicated by the direction of the force that is acting on a small positive charge that is placed in the field.
TYPES OF FIELDS:
There are two types of fields. They are:
Uniform field:
In a uniform field, the field lines are straight and are equally spaced out.
Variable field:
In a variable field, the field lines are curved and also equally spaced out.
PATTERN OF ELECTRIC FIELD OR ELECTRIC FIELD PATTERN:
Electric field pattern around a positive charge:
The electric field pattern around an isolated positive charge is a radial field that originates outward / come out from the terminal of the charge as shown in the figure below.
Diagram of field pattern around an isolated positive charge:
Electric field pattern around a negative charge:
The electric field pattern around an isolated negative charge is a radial field that terminate / enters / end at the terminal of the negative charge as shown in the figure below.
Diagram of field pattern around:
Electric field pattern around two negative charges:
The fields of the two similar charges repel one another because electric line of force do not cross one another and like charges repel one another. The field pattern is as shown below.
Note that the same thing is applicable to electric field pattern around two positive charges
Diagram of field pattern of two negative charges:
Electric field pattern around a positive and negative charges:
The electric field of the two unlike charges combined together because unlike charges attract one another.
Diagram of field pattern of two negative charges:
Electric field pattern of two parallel bar magnet of positive and negative charges:
The electric field of the two magnets combined together as shown in the figure below.
Diagram of field pattern of two magnets of positive and negative charges:
Electric field pattern of two parallel bar magnet of like charges:
The electric field of the two magnets repel one another because electric field do not cross one another and like charges repel one another. This is shown in the figure below.
Diagram of field pattern of two magnets of like charges:
PROPERTIES OF LINES OF FORCE:
Electric line of force has the following properties:
Field is a region as space within which the influence of an agent is field. Field is a vector quantity. It has magnitude and direction.
TYPES OF FIELD:
Field can be classified into scalar field and vector field.
SCALAR FIELD:
A scalar field is the type of field that has only magnitude and no direction. The direction of a scalar field can not determined or known.
EXAMPLE OF SCALAR FIELD:
The following are examples of scalar field:
- Temperature
- Volume
- Mass
- Distance
- Length
- Area
VECTOR FIELD:
A vector field is the type of field that has both magnitude and direction. The magnitude and direction of the field can be determined by either measurement or calculation using appropriate formulae.
EXAMPLES OF VECTOR FIELD:
- Gravitational field
- Electric field
- Magnetic field
1. GRAVITATIONAL FIELD:
Gravitational field is the region or space within which the influence of the force of gravity is felt. In gravitational field, work is done against the force of gravity. It act over a distance. It acts around every object that has mass. It is a force field. It influences the motion of object in the space where it operates.
GRAVITATIONAL ATTRACTION:
It is the earth’s attraction on every object that exit in its gravitational field. The effect of gravitational attraction is to change the velocity of object under its influence. That is to accelerate the object.
PROPERTIES OF A FIELD:
A field may be a scalar field or a vector field
The magnitude of a field can be determined by measurement or calculation
Some Field has directions
ACCELERATION DUE TO GRAVITY:
Acceleration due to gravity is the constant downward velocity of an object per second. It can also be defined as the acceleration of an object under the influence of gravity whose velocity per second is 9.8 m/s.
VALUE OF ACCELERATION DUE TO GRAVITY:
The value of acceleration due to gravity is 9.8 m/s². It is uniform in a given place and the same for all types of bodies irrespective of their masses. However, the value of acceleration due to gravity varies from place to place. It is minimum at the equator ( 9.78 m/s²) and increases with increase in latitude to reach a maximum value of 9.83m/s² at the pole of the earth.
ACCELERATION OF DIFFERENT OBJECTS RELEASED FROM THE SAME HEIGH IN A VACUUM:
When different objects of different masses are released from the same height in a vacuum, the objects fall to the ground at the same time because the same amount of acceleration due to gravity act on them all irrespective of their masses.
In the practical sense, When a stone and a feather are dropped from the same height at the same time, the stone fall faster and faster until it reaches the ground ahead of the feather. The feather falls slowly due to air friction or resistance which reduces the motion of the feather than that of the stone. Also, due to the large surface area of the feather , the feather falls more slowly than the stone.
FORCE OF GRAVITATIONAL ATTRACTION:
The force of gravitational attraction is the product of the mass of the object and the acceleration due to gravity that act on the object. It is given by the formula, force = mass * acceleration due to gravity
Force = mass * acceleration due to gravity.
Force = m*g
ACCELERATION OF FREE FALL DUE TO GRAVITY:
Acceleration of free fall due to gravity is the force of attraction on a unit mass or one kilogram mass of object.
When mass = 1kg, then force = mg = 1* g = g. Force = acceleration due to gravity. F = g
2.MAGNETIC FIELD:
Magnetic field is the region or space around a magnet within which the influence or force of a magnet is felt by a magnetic substance or a magnet. It is a vector field.
MAGNETS:
Magnets are substances that attract magnetic substances.
MAGNETIC SUBSTANCE:
Magnetic substance is a substance that can be attracted by a magnet.
EXAMPLES OF MAGNETIC SUBSTANCES:
The followings are magnetic substances:
- Iron
- Nickel
- Cobalt
- Zinc
MAGNETISM:
Magnetism is the ability of a magnet to attract magnetic substance. The magnetism of a magnet is concentrated at the poles of the magnet.
POLES OF A MAGNET:
Poles of a magnet is the ends of a magnet where the magnetic attraction or the magnetism of the magnet is concentrated.
POSITION OF A FREELY SUSPENDED MAGNET:
When a bar magnet is suspended freely by means of a rope about its centre, the magnet come to rest with its axis pointing approximately in the north – south direction. The end of the magnet that point in the northward direction is the north pole while the other end that point approximately in the southward direction is the south pole.
LAW OF MAGNET:
The law of magnetism States that like poles of magnets repel each other while the unlike poles attract each other.
MAGNETIC FIELD PATTERN OF A BAR MAGNET:
Magnetic field pattern of a bar magnet is the shape or direction of the magnetic line of force of a magnetic as it travels from the north pole of the magnet to the south pole of the magnet.
HOW TO PLOT MAGNETIC FIELD PATTERN OF A BAR MAGNET:
The magnetic field pattern of a magnet can be plotted in two ways :
With or using iron filling
Using a compass needle
PLOTTING MAGNETIC FIELD PATTERN USING IRON FILLINGS:
A thin sheet of glass is placed over a magnet and some quantity of iron fillings are sprinkled on the glass. The iron fillings arranged themselves in a clear and definite pattern on the glass. This pattern is the pattern of the magnetic field of the magnet.
PLOTTING MAGNETIC FIELD PATTERN USING COMPASS NEEDLES:
Place a sheet of paper on a drawing board. Place a bar magnet at the centre of the paper. Place three compass needles at the sides the magnet. The needles of the. Impasses swing and settle in the same directions. Mark n and s of each compass needles to represent the north and south poles of the compass needles. Join the nn and s together to get the magnetic field pattern of the bar magnet.
DIAGRAM:
MAGNETIC LINE OF FORCE OF A MAGNET:
Magnetic line of force of a magnet is the line along which a free north would move if it is placed in the field. It is also defined as the line such that a tangent to it at any point indicates the direction of the field at that pointDIRECTION OF A LINE OF FORCE AT ANY POINT:
It is a direction in which a free North pole that is placed at that point would try to move or follow
EXERCISES:
- Explain what is meant by a field mention three types of field you know…
- Distinguish between scalar field and vector field. Give two example for each.
- Define ( a ) gravitational field, ( b ) acceleration due to gravity. How does acceleration due to gravity varies with latitude?
- Explain why two solid bodies of different masses released from rest at the same point simultaneously fall to the ground at the same time. Is this observed when a feather and a coin are released in air? If not why?
- What do you understand by the poles of a magnet? Using a magnet of known poles , how can you differentiate between the two poles of another magnet?
- Explain what you understand by (I ) magnetic field, (ii) magnetic line of force. How can you plot the line of force in a magnet field of a bar magnet? Draw a diagram to show the arrangement of such line of force.
- The line of force of a magnet field do not cross, why is this so?
- Identity the force field from the following: density field, temperature field, gravitational field, magnetic field, electrostatic field, electric field.
- Which of the following will experience a force when placed in a magnetic field? Glass, plastic, iron, steel pin, paper pieces, aluminum
ELECTRIC FIELD:
Electric field is the region or space around a charge object within which the influence or force of electric charge is felt by another charged body.
It is a way of describing the action of one charge on another charge, from a distance.
ELECTRIC LINE OF FORCE:
Electric line of force is an imaginary line that is drawn in an electric field in such a way that the direction at any point indicate the direction of the electric field at that point.
Electric line of force can also be defined as the path which an isolated small positive charge would follow if placed in the field.
DIRECTION OF AN ELECTRIC FIELD:
The direction of an electric field is given or indicated by the direction of the force that is acting on a small positive charge that is placed in the field.
TYPES OF FIELDS:
There are two types of fields. They are:
Uniform field:
In a uniform field, the field lines are straight and are equally spaced out.
Variable field:
In a variable field, the field lines are curved and also equally spaced out.
PATTERN OF ELECTRIC FIELD OR ELECTRIC FIELD PATTERN:
Electric field pattern around a positive charge:
The electric field pattern around an isolated positive charge is a radial field that originates outward / come out from the terminal of the charge as shown in the figure below.
Diagram of field pattern around an isolated positive charge:
Electric field pattern around a negative charge:
The electric field pattern around an isolated negative charge is a radial field that terminate / enters / end at the terminal of the negative charge as shown in the figure below.
Diagram of field pattern around:
Electric field pattern around two negative charges:
The fields of the two similar charges repel one another because electric line of force do not cross one another and like charges repel one another. The field pattern is as shown below.
Note that the same thing is applicable to electric field pattern around two positive charges
Diagram of field pattern of two negative charges:
Electric field pattern around a positive and negative charges:
The electric field of the two unlike charges combined together because unlike charges attract one another.
Diagram of field pattern of two negative charges:
Electric field pattern of two parallel bar magnet of positive and negative charges:
The electric field of the two magnets combined together as shown in the figure below.
Diagram of field pattern of two magnets of positive and negative charges:
Electric field pattern of two parallel bar magnet of like charges:
The electric field of the two magnets repel one another because electric field do not cross one another and like charges repel one another. This is shown in the figure below.
Diagram of field pattern of two magnets of like charges:
PROPERTIES OF LINES OF FORCE:
Electric line of force has the following properties:
- Electric field lines originate on the positive charge and terminates on the negative charge.
- The numbers of field lines that start or end on a charge is proportional to the magnitude of the charge.
- Lines of force do not cross each other.
- Lines of force are straight, parallel and uniformly spaced in a uniform field.
- Lines of force indicate the direction of an electric field.
- Lines of force continue with any free charge.
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