Introduction to Magnetic Dipole
Magnetic dipole theory is being employed in a wide range of areas over the last half-century, including magnetic-fluid separation, magnetic localization, geophysical induction log, non-destructive research, magnetic fluid seal, prospecting, magnetic separation, and magnetic fluid damper. If the difference between magnetic dipoles is sizable (l > 10R), this principle about magnetic dipoles, which is centered on a restricted flow of electrical charge, can be used in theoretical calculations with high precision.
Whenever the range but also particle diameter are in that order of magnitude, the measurement error grows dramatically with declining range, and incorrect evidence has been found. Throughout the near-field region, the finite element model is a reasonably reliable process, but the measurement quantity is very large. As a result, the updated magnetic dipole study is inspired as a solution to this problem.
How does Repulsion or Attraction between Two Magnetic Dipoles Happen?
The power among two wires, both with a power supply, can be interpreted by the contact with one current to the other current magnetic fields. The force between two electrical conductors, for instance, which hold current in the same position is attractive.
When the current is in another direction it would be unattractive. Circular currents, placed on top of one another and corresponding to their planes, would attract if the forces would be in the same position but will repel while the currents are reversed. The condition is inverted when the circles are beside each other. The energy circulating in two currents in the same direction, both clockwise and reverse, is repulsive, although it is attracting in the reverse direction.
The strength of the observed loops could be measured by determining the orientation of the current in the nearest areas of the circuits: so the same orientation of the current leads to attraction; the reverse current direction leads to repulsion. Such an inherently complex energy across current loops might be more easily interpreted by considering the fields like they've been derived through magnetic dipoles.
As per his principle, with exception of poles, and repellent like poles, Coulomb developed an inversely-square law of forces for magnetic poles & electric current. The law of Coulomb currently applies just to charges, although it has traditionally been the basis for a magnetic potential similar to that of electricity.
An illustration of the force whereby a magnetic dipole is exposed is the orientation of the magnetic compass needle and the position including its external magnetic field. The torque's magnitude τ = mB sin ϑ. In this, ϑ was its angle from m to B. The torque μ aligns m to B. When the temperature is 90 °, it has its highest value, then when the dipole is the exterior field, it is null. The energy of a dipole, therefore, relies on its position concerning just the field and has been specified in joules units.
Magnetic Resonance Imaging (MRI)
MRI, also known as nuclear magnetic resonance imaging. MRI includes measuring, to generate high-resolution body and another anatomy framework representations in tissue with several atoms, more typically hydrogen concentrations, and the analysis of these measurement results. In the magnetic field, as hydrogen atoms are positioned, their nuclei (protons) appear to selectively coordinate their magnetic moment in the field direction.
The magnet energy potential of the nuclei is −mB. Turning the dipole moment direction needs 2mB of power because the potential energy throughout the current direction is +mB. A higher-frequency oscillator delivers power in the form of electromagnetic frequency v radiation, with each radiation source possessing a hv of energy, whereby h has been the Planck constant. There are high-frequency radio waves that are radiated from the electromagnetic radiation in the oscillatory and sent into the person's body during a heavy magnetic field.
The hydrogen core of the body tissue absorbs the radiation and reverses its direction when resonance state hv = 2mB is fulfilled. This resonance condition is satisfied anywhere at a given moment in a small body part, and energy absorption calculation shows the hydrogen concentration of atoms isolated in this area. A big solenoid with B from one to three teslas generates the magnetic field in an MRI scanner.
A series of "gradient coils" make sure the resonance is reached at all times in the confined area within the solenoid only; the coils are being used for moving the smaller target area so that the client's body could be scanned all over the place. The radiation v frequency is measured by a B value and is usually between 40 and 130 megahertz. The MRI technique will not affect the person since electromagnetic radiation intensity is significantly smaller than the thermal energy of a molecule in the human body.
Magnetization Effects in a Matter
A copper sample is drawn magnetically to the bottom field area to the right. This is called diamagnetic behavior. Conversely, in an effect called paramagnetism, an Aluminum sample is drawn into the elevated zone.
The exposure to the material to an external field produces a magnetic dipole moment.
A low concentration of matter is the magnetization M of the number (a vector sum) of magnet dipole moments in the smaller size that is separated by such a volume. M is calculated per meter in ampere units. The magnetic sensitivity of the substance χm determines the degree of triggered magnetization.
FAQs on Repulsion or Attraction Between Two Magnetic Dipoles
1. What is the fundamental rule for attraction and repulsion between two magnetic dipoles?
The fundamental rule governing the interaction between magnetic dipoles, such as bar magnets, is straightforward: like poles repel each other, while unlike poles attract. This means that if you bring the North pole of one magnet near the North pole of another, they will push each other away. Conversely, if you bring a North pole near a South pole, they will pull towards each other.
2. What factors determine whether the force between two magnetic dipoles is attractive or repulsive?
The nature of the force (attraction or repulsion) depends entirely on the relative orientation of the two dipoles. For example, with two bar magnets:
- End-to-end placement: If the magnets are placed in a line, a North pole facing a South pole results in attraction. A North pole facing a North pole results in repulsion.
- Side-by-side placement: If the magnets are parallel, placing them with North and South poles adjacent (N-S next to N-S) causes attraction. Placing them with like poles adjacent (N-S next to S-N) causes repulsion.
3. How is the force of attraction or repulsion between two short magnetic dipoles calculated?
The force between two short magnetic dipoles (with magnetic moments m₁ and m₂) separated by a distance r depends on their orientation. For the coaxial or end-on position, the magnitude of the force is given by the formula:
F = (μ₀/4π) * (6 * m₁ * m₂) / r⁴
Here, μ₀ is the permeability of free space. This formula shows that the force decreases rapidly with distance, proportional to the fourth power of the distance between their centres.
4. Why does the force between magnetic dipoles depend so strongly on their orientation?
A magnetic dipole consists of two poles (North and South) separated by a small distance. The total force between two dipoles is the vector sum of four separate forces: the force between the first magnet's North pole and the second's North and South poles, plus the force between the first magnet's South pole and the second's North and South poles. Because these individual attractive and repulsive forces act in different directions and have slightly different magnitudes depending on the alignment, their net result (the overall force) is highly dependent on the precise orientation of the dipoles relative to one another.
5. How does the distance between two magnetic dipoles affect the force between them?
The force between two magnetic dipoles diminishes very quickly as the distance between them increases. Unlike the inverse-square law (1/r²) for single electric charges or hypothetical magnetic monopoles, the force between two dipoles generally follows an inverse-fourth-power law (1/r⁴) for end-on configurations and an inverse-cube law (1/r³) for the potential energy. This rapid decrease occurs because the attractive and repulsive forces from the two poles of each magnet begin to cancel each other out more effectively at greater distances.
6. How do different types of magnetic materials react when placed near a magnet?
Materials exhibit attraction or repulsion based on their magnetic properties:
- Ferromagnetic materials (like iron, cobalt, and nickel) are strongly attracted to magnets.
- Paramagnetic materials (like aluminium and platinum) are weakly attracted to magnets.
- Diamagnetic materials (like copper, water, and gold) are weakly repelled by magnets.
Therefore, both attraction and repulsion are possible depending on the material's intrinsic magnetic nature.
7. What are some practical examples of attraction and repulsion between magnetic dipoles in technology?
The principles of magnetic attraction and repulsion are critical in many technologies. Key examples include:
- Electric Motors: Rapidly switching magnetic fields create continuous attraction and repulsion to turn a rotor, converting electrical energy into mechanical motion.
- Magnetic Levitation (Maglev) Trains: Powerful magnets on the train and track are oriented to repel each other, lifting the train to eliminate friction and allow for extremely high speeds.
- Magnetic Resonance Imaging (MRI): This medical imaging technique uses strong magnetic fields to align the magnetic dipole moments of hydrogen nuclei in the body to create detailed images of organs and tissues.
