Magnetic fields are usually produced by moving electric charges and the intrinsic magnetic moments of particles that are the elementary ones which are associated with a fundamental quantum property of their spin. The Magnetic fields and the electric fields are said to be interrelated and are both components of the forces which are electromagnetic and one of the four fundamental forces of nature.
The part which is of the magnet in a material that arises from a current which is applied externally and is not intrinsic to the material itself. Here, we are going to discover a few of the most important things related to it. The current is said to be expressed as the vector which is denoted by letter H and is measured in units of amperes per metre.
The definition of letter H is given as H = B/μ − M, where letter B is said to be the magnetic flux density. That is a measure of the actual magnetic field which is inside a material considered as a concentration of magnetic field lines or the flux and that too per unit cross-sectional area. The symbol μ denotes the magnetic permeability, and the capital letter M is the magnetization. The magnetic field also denoted by H might be thought of as the magnetic field which is produced by the flow of current in wires and the magnetic field B as the total magnetic field which is also the contribution to the field M made by the magnetic properties of the materials in the field.
Magnetic Field Intensity
A magnetic field is a field of the vector that describes the magnetic influence which is applied on moving electric charges or an electric current and magnetic materials. A moving charge that is in a magnetic field generally experiences a force which is perpendicular to its own velocity and to the magnetic field as well. A permanent magnet′s magnetic field usually is pulled on ferromagnetic materials for example as iron and repels or attracts other magnets. In addition to this, we can say that a magnetic field that varies with location will exert a force which is on a range of non-magnetic materials by affecting the motion of their outer electron atoms. The magnetic fields which generally surround magnetized materials and are created by electric currents such as those which are used in electromagnets and by the electric fields that are varying in time. Since, both the direction and strength of a magnetic field may vary with the location so they are described as a ma. A kind of map which is assigning a vector to each point of space is because of the way the magnetic field transforms under mirror reflection that is as a field of pseudovectors.
Unit of Magnetic Field Strength
In electromagnetics, the term "magnetic field" is generally used for two distinct but closely related fields of vectors which is generally denoted by the symbols denoted by B and H. In the International System of Units that is the SI unit, H magnetic field strength is measured in the SI base units that are of ampere per meter that is A/m. The symbol which is denoted by letter B is said to be the magnetic flux density that is said to be measured in tesla which in SI base units is kilogram per second per ampere.
Both the terms that are H and B differ in how they account for magnetization. In a vacuum, we can see that the two fields are generally related through the vacuum permeability, In a magnetized material the terms that generally differ by the material's magnetization at each point.
The magnetic fields that are usually used throughout modern technology particularly in electrical engineering and electromechanics as well. The magnetic field which is rotating is used in both electric motors and generators. We can say that the interaction of magnetic fields in electric devices such as transformers is conceptualized and investigated as magnetic circuits. Here we can say that the magnetic forces generally give information about the charge carriers in a material through the Hall effect. The planet Earth generally produces its own magnetic field which shields the planet that is earth's ozone layer from the solar wind and is important in navigation using a compass.
Magnetic Field Intensity Formula
The force that is said to be on an electric charge that generally depends on its location and the speed and direction which is two vector fields that are used to describe this force. The first is the electric field which generally describes the force that is acting on a charge that is stationary and that gives the component of the force that is independent of motion. The magnetic field which we have seen describes the component of the force that is proportional to both the direction and speed of charged particles. The magnetic field is generally defined by the law of the Lorentz force and is at each instant said to be perpendicular to both the motion of the charge and the force it experiences.
There are two different but we can say very closely related fields which are both sometimes known as the "magnetic field" written as letter B and H.
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FAQs on Magnetic Field Strength
1. What do you mean by magnetic field strength?
Magnetic field strength, denoted by the symbol B, is a vector quantity that describes the magnetic influence in a region. It determines the magnitude and direction of the force experienced by moving electric charges and magnetic materials. Visually, it is represented by the density of magnetic field lines; the closer the lines, the stronger the magnetic field.
2. What is the SI unit of magnetic field strength and how is it defined?
The SI unit for magnetic field strength (B), also known as magnetic flux density, is the tesla (T). One tesla is defined as the magnetic field strength that exerts a force of one newton on a charge of one coulomb moving at a velocity of one metre per second, perpendicular to the field. A smaller, non-SI unit often used is the gauss (G), where 1 T = 10,000 G.
3. What is the fundamental difference between magnetic field strength (B) and magnetic field intensity (H)?
This is a crucial distinction in magnetism, especially when dealing with materials.
- Magnetic Field Strength (B), or magnetic flux density, represents the total magnetic field within a material, including any magnetic response from the material itself. Its SI unit is the Tesla (T).
- Magnetic Field Intensity (H) represents the 'cause' of the magnetic field, produced purely by external electric currents, independent of the medium. Its SI unit is Amperes per metre (A/m).
4. How is the magnetic field strength for a current-carrying conductor calculated according to the CBSE syllabus?
For calculating magnetic field strength from a current source, two primary laws are used as per the CBSE Class 12 syllabus:
- Biot-Savart Law: This law is used to determine the magnetic field strength at a specific point due to an infinitesimally small segment of a current-carrying wire. It is the foundational law for calculating B-fields from various wire shapes.
- Ampere's Circuital Law: This law provides a more straightforward method for calculating the magnetic field in situations with high symmetry, such as for a long straight wire, a solenoid, or a toroid. It relates the line integral of the magnetic field around a closed loop to the net current enclosed by that loop.
5. How strong is a 1 Tesla magnetic field in comparison to everyday examples?
A 1 Tesla (T) magnetic field is exceptionally strong compared to what we encounter daily. Here are some comparisons:
- The Earth's magnetic field at the surface is about 30–60 microteslas (μT), which is more than 10,000 times weaker than 1 T.
- A typical refrigerator magnet has a field strength of around 5 milliteslas (mT), or 0.005 T.
- Medical MRI machines use powerful magnets, often in the range of 1.5 to 3.0 Tesla, which is why they require strict safety measures.
6. Why is the magnetic field inside a long solenoid considered uniform and strong?
The magnetic field inside a long solenoid is strong and nearly uniform due to the principle of superposition. The magnetic fields from the thousands of tightly packed, parallel loops of wire add up constructively inside the solenoid, creating a dense, straight, and powerful field. Outside the solenoid, the field components from the upper and lower sections of the wire largely cancel each other out, resulting in a very weak external field. The strength inside (B = μ₀nI) depends on the turn density (n) and current (I), not its diameter.
7. How are magnetic fields visually represented and what do the representations mean?
Magnetic fields are represented using imaginary magnetic field lines. These lines provide two key pieces of information:
- Direction: The tangent to a field line at any point gives the direction of the magnetic field at that point. By convention, they emerge from the North pole and enter the South pole externally.
- Strength: The density of the field lines (how close they are to each other) indicates the magnetic field's strength. Regions where the lines are close together have a strong magnetic field, while regions where they are far apart have a weaker field.
8. What is the primary source of Earth's magnetic field and why is it important?
The Earth's magnetic field is primarily generated by the geodynamo effect. This process involves the motion of conductive molten iron alloy in the Earth's outer core. The combination of this fluid motion, convection, and the planet's rotation creates electric currents that produce the magnetic field. This field is vital for life as it forms the magnetosphere, which deflects harmful charged particles from the solar wind, protecting our atmosphere and electronics.
