In physics and electrical engineering, a conductor is an object or type of material that permits charge (electric current) to travel in one or more directions. Metal materials are common electrical conductors. The passage of negatively charged electrons, positively charged holes, and, in rare situations, positive or negative ions creates an electric current.
It is not necessary for one charged particle to travel from the component producing the current (the current source) to those consuming it for current to flow within a closed electrical circuit (the loads). Instead, the charged particle must nudge its neighbour a finite amount, who will then nudge their neighbour, and so on, until a particle is nudged into the consumer, supplying electricity.
What is happening is essentially a long chain of momentum transfer between mobile charge carriers; the Drude model of conduction describes this process more precisely. This momentum transfer model makes metal an excellent choice for a conductor; metals, in general, have a delocalized sea of electrons, which allows the electrons to collide and thus affect the conductor.
Fleming’s left-hand rule for electric motors is one of two visual mnemonics for electric motors, the other being Fleming’s right-hand rule (for generators). They were invented in the late nineteenth century by John Ambrose Fleming as a simple method of determining the direction of motion in an electric motor or the direction of electric current in an electric generator.
The information about carrying conductors from various physics-related articles are available here. Carrying conductors in a magnetic field and its general concepts are important topics in physics. Students who want to flourish in physics need to be well known about earth magnetism to get deep knowledge about it to do well on their exams. The definition, working principle, and diagram of the streamline flow are provided here to assist students in effectively understanding the respective topic. Continue to visit our website for additional physics help.
When a current-carrying conductor is in a magnetic field, the interaction between the magnetic field and the magnetic field created by moving charges in the wire produces a force. Fleming’s left hand rule can be used to establish the force’s direction. A magnetic field is generated by the current-carrying wire.
A magnetic field outside the body interacts with this. When two magnetic fields collide, the direction of the external magnetic field and the direction of current in the conductor determine whether they attract or repel one another. Moving charges are subjected to a force in a magnetic field. If these moving charges are in a wire, the wire should be exposed to a force.
When current flows through a conducting wire and an external magnetic field is applied across it, the conducting wire experiences a force that is perpendicular to both the field and the direction of the current flow (they are mutually perpendicular). A left hand can be used to indicate three mutually orthogonal axes on the thumb, forefinger, and middle finger, as illustrated in the figure.
Then, for each finger, a quantity is assigned (mechanical force, magnetic field, and electric current). The right and left hands are used to operate generators and motors, respectively.
When a current-carrying conductor is in a magnetic field, it experiences a force as a result of the interaction between the magnetic field and the field (magnetic) produced by moving charges in the wire. Fleming’s left-hand rule can be used to establish the force’s direction. A magnetic field surrounds the current-carrying conductor.
This interacts with a magnetic field outside of the body. When two magnetic fields interact, they exhibit attraction and repulsion based on the direction of the external magnetic field and the direction of current in the conductor.
Force between two parallel current-carrying conductor
We discovered the existence of a magnetic field as a result of a current-carrying conductor and Biot – Savart’s law.
We also discovered that an external magnetic field exerts a force on a current-carrying conductor, as well as the Lorentz force formula that governs this principle.
As a result of the two studies, we can conclude that any two current carrying conductors placed close together will exert a magnetic force on each other. This case will be discussed in greater depth in this section.
Consider the system depicted in the diagram. As illustrated in the image, we have two parallel current-carrying conductors separated by a distance ‘d’, with one carrying current I1 and the other carrying current I2. We can deduce from the previous knowledge that conductor 2 is subjected to the same magnetic field at every point along its length due to conductor 1.
The magnetic force direction is shown in the diagram and can be determined using the right-hand thumb rule. As can be seen, the magnetic field is directed downwards by the first conductor.
The magnitude of the field due to the first conductor can be calculated using Ampere’s circuital law:
The force applied by conductor 1 on a conductor 2 segment of length L can be calculated as follows:
Similarly, the force exerted by conductor 2 on conductor 1 can be calculated. We can observe that conductor 1 is subjected to the same force as conductor 2, but the force is applied in the opposite direction. Thus,
F12 = F21
We also notice that currents flowing in the same direction attract the conductors and currents flowing in the opposite direction repel the conductors. The magnitude of the force acting per unit length can be expressed as follows:
Direction of current flow:
The direction of an electric current is, by convention, the same as the direction of a positive charge. As a result, the external circuit’s current is diverted away from the battery’s positive terminal and toward the negative terminal. Electrons would actually move in the opposite direction through the wires. Those who have been taught that current flows from positive to negative may find it difficult to understand the direction of electric current flow.
This phenomenon is explained by two theories. The first is the conventional current theory, and the second is the actual current flow theory. The structure of an atom and atomic particles were unknown when Benjamin Franklin was studying charges. As a result, he assumed that the point of charge accumulation was positive and the point of charge deficiency was negative. As a result, the charge is said to be flowing from positive to negative.
However, an electric current is nothing more than the flow of electrons. Electrons are negatively charged particles that are drawn to positive charges. Furthermore, numerous experiments have revealed that free electrons in a conductor flow.
Electrons that are negatively charged move from the negative terminal to the positive terminal. This is the actual current flow direction.
Because of the presence of metallic fluids in both the outer and inner cores, the earth generates its own magnetic field lines. The outer core is made up of molten iron, while the inner core is made up of solidified elements. Convection currents of molten iron and nickel in the earth’s core generate magnetism.
These currents carry charged particle streams and generate magnetic fields. This magnetic field deflects ionizing charged particles from the sun (referred to as solar wind) and keeps them from entering our atmosphere. Without this magnetic shield, the solar wind could have gradually destroyed our atmosphere, eradicating life on Earth.
Mars lacks a strong atmosphere capable of supporting life because it lacks a magnetic field to protect it. The magnetic poles of the Earth are not parallel to the geographic north and south poles. Instead, the magnetic south pole is located in Canada, and the magnetic north pole is located in Antarctica. The magnetic poles are inclined by about 10 degrees to the rotational axis of the Earth.
So, all along, your compass had been pointing to Canada rather than the true North.
The magnetic North pole is located in Northern Canada to the south; the geographic South pole is located in the center of the Antarctic continent, but the magnetic pole is hundreds of miles away, near the coast. Compasses are virtually useless in areas near the magnetic poles.
Laminar flow and turbulent flow
Laminar flow is the movement of fluid particles along well-defined paths or streamlines that are all straight and parallel. As a result, the particles move in laminar or layer motion, gliding smoothly over the next layer. Laminar flow occurs in small diameter pipes with low velocities and high viscosity fluid.
This flow is also known as streamline flow or viscous flow. Oil flow through a thin tube, blood flow through capillaries, and smoke rising in a straight path from an incense stick are all examples of laminar flow. However, as it eddies from its regular path, the smoke transforms into a turbulent flow after rising to a small height.
Turbulent flow is defined as the movement of fluid particles in a zigzag pattern. The formation of eddies occurs as a result of the zigzag movement of fluid particles, which is responsible for high energy loss. The magnitude and direction of the fluid’s speed at a point change continuously in a turbulent flow.
Turbulent flow is common in large diameter pipes with high-velocity fluid flow. CFD analysis is the primary tool for analyzing turbulent flow. CFD is a branch of fluid mechanics that analyses and solves problems involving turbulent fluid flows using algorithms and numerical analysis.
The Navier-Stokes equation or simplified Reynolds-averaged Navier-Stokes equations are widely accepted as the foundation for virtually all CFD codes.
An experiment with ink in a cylindrical tube can be used to visualize the laminar flow. The ink is injected into the center of a glass tube filled with water. When the water’s speed remains slow, the ink does not appear to mix with it; the streamlines are parallel and are referred to as laminar flow. When the speed of the water increases, there will be a sudden change.
The flow is then completely disrupted, and the water becomes homogeneous as it passes through the ink. As a result, the streamlines are chaotic rather than linear, and the flow is referred to as turbulent flow.
Also read: Important Topic of Physics: Ammeter
Frequently Asked Questions (FAQs):
Question: Is the Earth’s magnetic field different in different places?
Answer: Yes, the magnetic field varies depending on where you are. The magnetic field is affected by both location and time. Satellites and approximately 200 operational magnetic observatories around the world, as well as several more temporary sites, are used to measure the distribution of the magnetic field.
Question: What is the horizontal component of the earth’s magnetic field and what is the angle of dip at the location where a magnetic needle is free to rotate in a vertical plane?
Answer: Because the magnetic needle is free to rotate in a vertical plane, the horizontal component of the Earth’s magnetic field is zero. This location has a 900-degree angle of dip.
Question: What causes the earth’s magnetism?
Answer: The earth’s magnetism is caused by circulating ions that are highly conducting in the earth’s core, resulting in the formation of current loops. The magnetic field is formed as a result of these current loops.