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Introduction to electricity and Magnetism
In simpler words, the force developed by the moving charges of electricity is called Magnetism. The magnetic field is where magnetic effects are observed around the magnet or current-carrying conductors. The overall phenomenon is termed Field Magnetism. Moreover, this study was proposed by Christian Oersted. Furthermore, Magnetism is one of the broad fields of science. However, every aspect, including Lorentz force and Biot-savart law, is given below. Let’s dive directly into the lesson.
Moving Charges and Magnetism: History
The finding made by Hans Christian Oersted demonstrated a strong link between the two. When a pivoted magnet was maintained near a wire carrying an electric current, it deflected, according to Oersted. Thus, Oersted’s study revealed that moving electrical charges might cause magnetic effects. Electromagnetic waves are also a branch of physics that deals with Magnetism caused by an electric current.
Lorentz Force
Consider a point charge q (flowing with a velocity of v and positioned at r at a certain time t) in the vicinity of both the electric and magnetic fields E (r) and B(r). The force exerted by both of them on an electric charge q is given by,
F = q [E (r) + v × B (r)] ≡ FElectric + FMagnetic
An examination of this phrase reveals the following:
- Lorentz’s Force is determined by q, v, and B. (charge of the particle, the velocity, and the magnetic field). The force exerted by a negative charge is the polar opposite of that exerted by a positive charge.
- A vector product between velocity and the magnetic field is included in the Magnetism. If the velocity and magnetic field are parallel or antiparallel, the force due to the magnetic field is 0. The force works perpendicular to both the velocity and the magnetic force in a (sideways) direction.
Law of Biot-Savart
Consider the conductor’s infinitesimal element dl. The magnetic field dB produced by this element must be measured at a position P that is r away from it. Let the angle between dl and the location vector r be theta. The direction of dl is the same as the current direction.
Biot-Savart law describes the magnetic field induced by a current-carrying portion. A dimensionless parameter is calculated in this section. A current-carrying wire loop generates a strong magnetic B(r), whereby r is the distance between the coil’s centre and the magnetised point. The current I inside the coil is proportional toward the applied field B. The strength and direction of the field are regulated by r. Its vector notation is as follows.
Circuital Law of Ampere
A closed-loop integral is a formula for this. The product of current confined by the path and permeability of the medium equals the integral of magnetic field density (B) along an imagined closed path. The coil’s magnetic field has a line integral of μo times the current travelling through it. It may be stated numerically as
∫B⋅dl=μoI
Magnetic force on a current-carrying conductor
A current-carrying conductor is subjected to a magnetic force.
The magnetic force on a long, current-carrying conductor having length l and current I in a uniform magnetic field B is given by
F=I (I×B) or |F|=I|lB|sinθ.
Fleming’s Left Hand Rule may be used to find the direction of F, which is perpendicular to both I and B.
Charged particle motion in a magnetic field
If a force on a particle contains a component parallel to (or opposite to) the particle’s motion, the force accomplishes work.
When a charge moves through a magnetic field, the magnetic force is perpendicular to the particle’s velocity.
As a result, no effort is made, and there is no change in the magnitude of the velocity.
There are two sorts of situations that can occur:
- When v is perpendicular to B, this is the first case.
- When v makes a different angle with B than 0o
Moving Coil Galvanometer
A moving coil galvanometer is a strong electromagnetic device for measuring current. Even though the voltage is relatively weak, it can properly measure it. A Moving Coil Galvanometer is composed of two main sections:
- The Weston galvanometer, also known as the Pivoted-coil Suspended
- Coil galvanometer is a type of suspended coil galvanometer.
Although the device is highly sensitive, it can be employed to monitor power from any of the connections. It displays no energy flow through the instrument or null deflection when linked to the Wheatstone’s bridge circuit. The arrows swing to the right and left, relying just on the path of the stream flowing.
Galvanometer as ammeter
As an ammeter, a galvanometer is used.
The galvanometer cannot be used as an ammeter to measure the current in a circuit on its own. This is due to two factors. A galvanometer is a highly sensitive instrument, and a current on its order produces a full-scale deflection. The galvanometer must be linked in series to measure currents, and because it has a high resistance, this will modify the current value in the circuit.
Galvanometer as Voltmeter
As a Voltmeter, a Galvanometer is used.
To use a galvanometer to determine the potential difference between two circuit sections, they must be connected parallel. Furthermore, it must take very little current; else, the voltage measurement will cause a significant degree of disruption to the original configuration. Typically, we try to limit the amount of noise caused by the measurement instrument to 1%. A substantial resistance R is connected in series with the galvanometer to achieve this.
Cyclotron
It’s a device that boosts the energy of charged particles or ions. The cyclotron increases the energy of charged particles by combining electric and magnetic fields. The fields are termed crossed fields because they are perpendicular to one another.
The cyclotron due to a uniform perpendicular magnetic field B, a source of charged particles or ions at P, travels in a circular pattern in the Dees, D1and D2. These ions are accelerated to high speeds by an alternating voltage source. At the exit port, the ions are finally ‘extracted’.
Conclusion
We came through different aspects of Moving Charges and Magnetism from all the above. We concluded that the moving charges are the by-product of electricity and Magnetism. Since Magnetism is the field of science in itself, it has many concepts. Lorentz force, the law of Biot-savart, and the circuital law of Ampere are some of the main among them concluded today.
