Category: Physics Notes PPT

A battery is an electronic device that changes over chemical energy into electrical energy to give a static electrical charge to power. Though a capacitor is an electronic part that stores electrostatic energy in an electric field. Both the capacitor and battery play out a similar capacity of putting away and discharging energy, be that as it may, there are basic contrasts between capacitor and battery in the manner they work. 

Albeit the two batteries and capacitors play out a similar capacity of putting away energy, the primary distinction between them lies in the manner they play out this task. Battery stores and disperse energy straightly while capacitors store and circulate energy in short blasts. In this article, we will study in detail about what is the difference between a capacitor and a battery. Let us look at what the capacitor vs battery is. 

What is Battery?

A battery is an electronic device made of at least one cell that changes over the chemical energy stuffed inside its dynamic materials into electrical energy to give a static electrical charge to power. 

Electrons are created through electrochemical reactions which include the move of electrons by means of an electronic circuit. 

In straightforward terms, the battery is a consistent wellspring of power that supplies electricity as a direct current (DC). A battery, for the most part, contains a positive (+ve) and a negative (- ve) terminal. 

The cell is the essential power unit of the battery which comprises three primary bits. In addition, there are two electrodes and a chemical called an electrolyte that fills the hole between the electrodes. 

At the point when the electrodes are associated with a circuit, the electrons cross from the negative to the positive terminal, in the long run making an electrical charge. Energy is stored inside the battery as chemical energy which gets changed over into electrical energy, discharging electricity through a chemical reaction which in the end generates an electric current.

Some Common Terminologies Used while Talking About a Battery:

Some of the terms that you will frequently come across while studying about a battery are:

• Cell: It refers to a single cathode and anode that is separated by an electrolyte. The cells are used to produce a current and a voltage. One or more cells put together make up a battery, for example, car batteries generally contain six cells.

• Primary Cell: This term refers to those cells that contain chemicals that cannot be reversed and have to be thrown away once dead.

• Secondary Cells: These are the cells whose chemistry can be reversed and therefore, they are recharged multiple times. These cells are also known as rechargeable batteries.

• Nominal Voltage: It refers to the voltage that is stated by the manufacturers. 

• Capacity: It is the measure of the electric charge that a battery can deliver at a specific voltage. The capacity of a battery is generally rated in amp-hours (Ah) and milliamp-hours (mAh).

• C-Rate: It refers to the discharge current in powerful batteries like lithium-ion batteries. It is a more appropriate method of denoting discharge current as it makes the attributes of the current more clearly defined. 1C refers to the quantity of current required to discharge the battery in an hour. Therefore, a 400 mAh battery rated as 1C would supply a current of 400 mAh. Similarly, a 400 mAh battery rated as 5C would supply a current of 2 A. 

What is Capacitor?

A capacitor (otherwise called a condenser) is likewise an electronic part that stores electrostatic energy in an electric field. 

They are progressively similar to a battery however they are utilized for totally unique reasons. While a battery utilizes chemical reactions to store electrical energy and discharges power gradually through an electronic circuit, capacitors are fit for discharging energy quickly. 

A capacitor contains in any event two electrical conductors separated by an insulator (dielectric). At the point when an electric field creates over the insulator, it stops the flow and an electric charge is beginning to develop on the plates. 

What are the Factors that one should Consider while Choosing a Capacitor?

There are certain points that one should keep in mind while choosing a capacitor. These factors include:

1. Size: according to your need, you must choose the physical volume and capacitance of your capacitor.

2. Maximum Voltage: you must consider the maximum voltage of the capacitor as the voltage exceeding the maximum voltage will result in the destruction of the capacitor.

3. Leakage Current: you must also look into the leakage current while choosing your capacitor as even nanoamps of current loss will cause the energy of the capacitor to drain out slowly and gradually.

4. Equivalent Series Resistance: the tiny amount of resistance developed at the terminals of the capacitor can create a problem when a lot of current runs through it as it can lead to the production of heat and power loss as well.

5. Tolerance: one must also check the tolerance level of the capacitors while choosing a capacitor. 

Difference Between Capacitor and Battery 

1. Meaning of Capacitor and Battery: While a battery stores its potential energy as chemical reactions before changing over it into electrical energy, capacitors store potential energy in an electric field. In contrast to a battery, a capacitor voltage is variable and is relative to the measure of electrical charge stored on the plates.

2. Use of Capacitor and Battery: A battery can as a rule store a bigger measure of electrical charge, while a capacitor, then again, is equipped for dealing with high voltage applications and perfect for high-frequency employments. 

3. Charge/Discharge Rate of Capacitor and Battery: The rate at which a capacitor can charge and discharge is typically quicker than what a battery is equipped for in light of the fact that a capacitor stores the electrical energy directly onto the plates. The procedure gets postponed a piece if there should arise an occurrence of a battery because of the chemical reaction included while changing over chemical energy into electrical energy. 

4. Energy Storage of Capacitor and Battery: While both electronic devices are utilized to store electrical energy, the manner in which they do fluctuate drastically. A battery stores electrical energy as chemical energy, while a capacitor stores electrical energy in an attractive field. This is the reason batteries store a great deal of charge however they charge/discharge gradually. 

5. The Polarity of Capacitor and Battery: The polarity of the electronic circuit must be opposite while charging a battery, while it must be the same as it should be while utilizing if there should be an occurrence of a capacitor. A battery keeps up a steady voltage flow over the terminals and it is discharged just when the voltage goes down.

What are the Similarities Between a Battery and a Capacitor?

Though there are many differences between a battery and a capacitor, the two of them also share certain essential similarities with each other. The major similarities between a battery and a capacitor are:

• Both the batteries and the capacitor are capable of storing electrical energy.

• Both the capacitor and the batteries have a series of resistance.

• Both the capacitor and battery have the capability of producing a potential difference across any electrical component connected to it, for example, a resistor.

To know more about batteries, capacitors, and their differences, log on to and seek deeper insights from expert mentors. Clear your concepts and queries under the guidance of the best teachers and develop a conceptual foundation. 

The information or the data is available in audio, video, written and in other forms. To transmit these data radio signals are used. The transmission takes place with the help of radio carriers. The process of converting and transmitting the data into radio signals by the addition of information to an optical or electronic carrier signal is called Modulation. Usually, a carrier signal has a steady waveform i.e. it has constant frequency and amplitude. The data is added to the carrier wave by varying its frequency, amplitude, polarization, spin and phase. Modulation has wide applications in radio, optics/laser and computer networks.

There are three basic types of modulation,

1. Frequency Modulation (FM)

2. Amplitude Modulation (AM) &

3. Phase Modulation (PM)

As Phase Modulation and Frequency modulation works on the same principle, they are considered as the inter-related.

We shall now discuss FM and AM one by one.

What is Frequency Modulation?

In frequency modulation, the amplitude of the signal is constant but the frequency is modified according to signals being sent. It is developed by Edwin H. Armstrong, an American electrical engineer. To overcome the effect of noise and interference with other signals rising due to thunderstorm and eddy currents generated in transmission devices, a method of Frequency Modulation is used. As these interferences can easily affect the magnitude of the amplitude but cannot diversify frequency, FM is preferred by users.

There are many techniques used for Frequency Modulation.

1. Varactor diode Oscillator– In this technique, a varactor diode is placed within the circuit to modulate frequency. This method gives only narrow band transmissions.

2. Phase Locked Loop– This technique provides excellent FM. In this method, phases are constrained within the loop to modulate frequency.

Frequency Modulation Equations

Let,

m(t) – modulating signal

Am – Amplitude of the modulating signal.

ωm – Angular frequency of the modulating signal.

Ɵ – is the phase of the modulating signal.

Then,

FM equation can be represented as,

m(t) = Am cos (ωmt + Ɵ)

Deviation of frequency Δfmax is given by the expression,

Δfmax =   fmt-fc׀

       =  K Am Cos (2 π fm t)

Modulation index is given by,

μ=fm Δfmax = fmKAm

Advantages of Frequency Modulation

1. The main advantage of FM is, it is less susceptible to noise and other interferences during transmission of signals. As the only frequency modulation takes place, transmission remains unaffected.

2. It can be used for low power transmitters.

3. For an expected output, less battery power is required and thus can be used for two-way radio applications.

Disadvantages of Frequency Modulation

1. The equipment cost for FM is higher. Also, it gives larger bandwidth.

2. The output is small compared to other types of modulations.

3. For better transmission you need closely placed antennae.

What is Amplitude Modulation?

The transmission of data by radio carriers with the help of addition of signals in which frequency is kept constant and amplitude is modulated, is known as Amplitude Modulation. It is widely used in electronic communications. For transmission of long, medium and small waves, AM is widely used.

There are two methods of Amplitude Modulation

1. Low- level Generation– In this method of AM, frequency less than the desired frequency is generated and then later amplitude is modulated.

2. High- level Generation– In this technique, the gain of the transmitter final output is amplified.

Amplitude Modulation Equations

The Amplitude Modulation equation is given as,

y(t) = A.sin(ωct)+A M2[sin((ωc+ωm)t+φ)]+A M2[sin((ωc−ωm)t−φ)]

where,

  C- the carrier amplitude

   φ- phase of the signal at the start of the reference time

   M – carrier amplitude

Modulation Index is given by,

μ= Ac/Am=Amplitude of carrier wave/ Amplitude of modulating signal

Types of Amplitude Modulation

There are three types of Amplitude Modulation

1. Single sideband (SSB) modulation– In this type of AM, the modulation wave consists either of the upper sideband or the lower sideband.

2. Double sideband-suppressed carrier (DSB-SC) modulation– In this type of AM, the transmitted wave consists of only the upper and lower sidebands still bandwidth remains the same.

3. Vestigial sideband (VSB) modulation-Here, one sideband is transmitted almost completely and just a part of the other sideband is taken. The required bandwidth is in excess amount.

 

Advantages of Amplitude Modulation

1. Amplitude Modulation is cheaper.

2. It is simple to implement and it can be demodulated easily.

3. The receivers of AM do not need special arrangements and they are inexpensive.

Disadvantages of Amplitude Modulation

1. The efficiency is very low as it needs a lot of power.

2. It uses the amplitude frequency many times to control the signals by radio carrier.

3. The quality of the original signal on the receiver is poorer.

4. The Amplitude Modulation systems are prone to disturbances like noise and interferences of the external causes.

5. The applications are limited to one to one communication only
   .

Pounds and kilograms are both units for measuring mass. Pound refers to an imperial system of measuring weight or mass. Kilogram, on the other hand, was adopted under the SI or International System of Units in 1959.  

However, there are incremental differences when calculating mass in kilograms as opposed to the same calculation in pounds. How many kg in one pound is a common query for many individuals trying to compound the mass of an object from kilogram to pounds, or vice versa.

One Pound is Equal to How Many Kgs 

One pound is equal to just under half a kilogram. To be exact, 

1 pound = 0.453 kg

By this same equation, one can derive how many pounds in a kilogram.

1 kg = 2.204 pounds

Before proceeding to learn the difference between pound and kg, let us understand a bit more about kilogram and pound.

History of Kilogram 

A kilogram is referred to as the basic unit of mass in the metric system. 

In 1795, a kilogram was originally defined as the mass of one litre of water. It was the platinum Kilogramme des Archives that replaced it as the standard of mass in 1799. 

In 1899, it was superseded by a standard kilogram (also a solid cylinder), whose height was equal to its diameter, and was made of the same platinum-iridium alloy as the bar that was then used to be the standard for defining the metre. 

In 2011, the General Conference on Weights and Measures or CGPM came up with a proposal that focused on redefining the kilogram by a fundamental physical constant instead of a physical artefact. The Plank’s constant was chosen as the fundamental physical constant. This was done with the main aim of avoiding the issue of having the kilogram defined by an object that had a changing mass. And at the 2018 CGPM, the said proposal was accepted and was put to an application from May 2019. 

What is Kilogram?

Under the SI system of measurement, a kilogram is considered equal to the mass of one litre of water. Stored in a vault at the International Bureau of Weights and Measures, France, IPK is a standard Iridium-Platinum cylindrical figure that is exactly equal to 1 kg. To understand the relation between pound and kg, you should also learn more about a pound.

History of Pound 

​​The lbs meaning of weight comes from the Latin word “pondus” which happens to be the unit of weight. 

The term pound dates back a long time. It was first said to have originated as a result of Charlemagne’s reform with regard to currency in the Frankish Empire. 

In Mediaeval England, there were several derivations used of the libra (the libra is the Roman ancestor of the modern pound) vied for the purpose of general acceptance. Amongst the earliest of these, the Tower Pound (it is called the Tower Pound as its standard used to be kept in the Royal Mint in the Tower of London) was applied to certain precious metals as well as drugs and contained about 5,400 grains (o.350 kg) whereas the mercantile pound contained about 6,750 grains (0.437 kg). 

Now, the word pound that happens to be an English word, is connected to a lot of different countries. For instance, German Pfund, Swedish Pund, and Dutch Pond. All these countries are known to derive from a borrowing into Proto-Germanic of a Latin expression; the expression is lībra pondō wherein the adverb pondō means “by weight” and happens to be related to the noun pondus/weight; the expression as a whole, thus refers to “a pound by weight” 

What is Pound?

A pound is one of the units of measuring mass under the Imperial system. Other scales include stone and ounce. Abbreviated as ‘lb’ due to the pound’s association with the Roman Libra, this unit has several varieties in different countries.

The exact answer to how many kg in one pound is 0.45359237 kg. Nonetheless, remembering this figure is difficult, which is why most calculations consider 1 pound = 0.450 kg.

Multiple Choice Question – 1

Raj Buys 10 Pounds of Potato. How many Kg of potato did he buy?

1. 4.23 kg

2. 6.53 kg

3. 4.53 kg

4. 3.73 kg

Ans: (c) 4.53 kg

Differences Between Kg and Pound

Pounds to Kilogram Formula

Being able to answer how many kg in one pound is not sufficient. You should also be able to convert pounds into kilograms quickly, as well. To do so, simply multiply the mass in kg with 0.453. For example, 3 pounds will be equal to 3 x 0.453 kg.  

Kilogram to Pounds Formula

In a similar fashion, when converting mass from kilogram to pounds, multiply the weight in kg with 2.204.

Now that you know the difference between kg and pound, here is a quick exercise to solve.

Exercise – 1

Q. Shruti orders 45 pounds of cement for the construction of her home. However, she receives only 13 kg of cement. How many pounds of cement does she need to complete her order?

Solution: 

Method 1

Start by converting 45 pounds into kg.

Thus, cement ordered (in kg) = 45 x 0.453 = 20.38kg    

Shruti received 13 kg of cement from her order. Thus, cement still to be delivered is (20.41 – 13) kg. Therefore, she is yet to receive 7.38 kg of cement. 

Pounds of cement yet to be delivered = 7.38 x 2.20 = 16.236 pounds.

 

Method 2

This is the faster procedure, involving just one conversion.

Start by converting 13 kg into pounds.

Cement delivered = 13 x 2.204 = 28.65 pounds.

Cement to be delivered = 45-28.65 = 16
.35 pounds 

The calculation becomes extremely simple when one can remember the lbs to kilos formula.

One pound vs kg calculations can become easier with help from ’s wide array of tricks and tips. We even offer a app for students to ensure enhanced connectivity. Through this application, students can attend classes and learn more about particular chapters, topics and subjects.

Difference Between Mass and Weight

Did You know? 

The kilogram was said to be the last of the SI units that were defined by a physical artefact! 

We know that a battery has a positive and a negative terminal. As soon as the voltage is applied to the circuit, pressure or electric tension generates inside it because of some difference called the potential difference. 

Now, this pressure pushes the charged electron to move from the negative terminal of the battery to the positive. This movement of electrons from a negative terminal to a positive is what we call the current. 

This article discusses the current as of the flow of electrons, and the voltage responsible for pushing the current from one end to the other, and the current voltage difference. 

How to Differentiate the Current from Voltage?

Now, we will discuss the difference of voltage and current:

From the above statement, the voltage was labeled as an electric tension, electric pressure, and the potential difference. 

We know that the voltage is generated at the power station. Electrons move randomly inside the circuit, and to give a direction to the electron flow from a negative terminal of a battery to the positive, some push is required; that push is the voltage.

To understand what voltage is, we will consider an example of a water tank.

Let’s suppose that an empty water tank is placed below the filled tank. Now, as soon as the tap is opened, the water starts flowing out of the upper tank. However, this happens only when pressure is applied to the water in the upper tank. 

Similarly, on connecting the circuit to the battery, a difference generates across its ends. The difference coming out from an electric circuit’s power source is called the potential difference/voltage.

The voltage/electric pressure pushes the charged electrons to migrate from the negative end of the battery to the positive side and continues to loop inside the circuit/conducting loop, the flow of electrons produces the current inside the circuit.

Now, these charged electrons or the current do the work in the form of lighting a bulb.

Thus voltage is the electric tension/pressure that forces the electrons (current) to flow through the circuit that generates electricity, and the bulb glows.

Differentiate Between Current and Voltage

The below table lists the difference between voltage and current: 

Current vs Voltage

Now let’s take another example to understand how voltage and current are related to each other.

Let’s suppose that a water tower is placed standing in a river and it is filled with water. Now, the water tower has enough potential energy to do work. The pump, connected to its right-hand side, and to complete the circuit, a pipe is connected to the left of the tower.

This pump generates pressure on the water tower, which in turn, pushes the water out of the pipe. On increasing the width of the pipe, the potential energy of the tower remains the same, however, the volume of the water flowing out of the pipe increases. Even if we remove the pipe, the potential energy still remains the same. 

So, here pressure is the voltage, and water flowing out of the pipe is the current. 

This is what we have seen in the remote cells, whether connected to the circuit or left idle, the voltage of the cell remains the same.

Points to Remember

V ∝ I

The current flowing through the circuit is directly proportional to the push offered by the circuit to the flow of electrons in a particular direction.

It means the more is the pressure, the more is the water flow or the current flow in the circuit, and vice-versa.

If the potential difference between the two points of the pipe through which water flows is increased, the voltage also increases. It’s because the voltage is the potential difference between two points.

 

How Will Help Me With Understanding The Difference Between Voltage And Current?

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The difference between Voltage and current is a very basic concept and can be understood by the simple concept of cause and effect. This concept says that two quantities are said to be cause and effect if one happens because of the effect of the other. For example, water is flowing from the tap because it is turned on. The act of turning on the tap is the cause and the act of water flowing is its effect. Hence, in similar terms, we can say that because of the existence of voltage between the two terminals, the current flows between those two terminals. Hence, voltage is the cause and current is its effect. There are also many prominent differences that exist between voltage and current. High voltage does not necessarily mean higher current flows in the circuit and similarly, low current does not mean there is a voltage difference in the circuit. There exists another quantity that determines the relationship between voltage and current. This quantity is called resistance in the circuit. This relationship is explained with the help of Ohm’s law which students can learn on .

Further, these concepts are explained in in detail and in an easy to understand way so that students can grasp them and answer any questions related to them. Students will find more such basic concepts and great tips to learn them on . 

Line voltage in a three-phase system is the potential difference between any two lines or phases present in the system, denoted by V_line or V_L-L. The phases present here are conductors or windings of a coil. If R, Y and B are the three phases ( red phase, yellow phase, blue phase ) then the voltage difference between R and Y, Y and B or B and R forms the line voltage. Phase voltage, on the other hand, is the potential difference between one phase (R, Y or B) and neutral junction point, denoted by V_phase = V_R (voltage in red phase) = V_Y (voltage in yellow phase) = V_B (voltage in blue phase).

 

Similarly line current is the current in one phase while phase current is the current inside the three-phase connection.

 

To understand line voltage and phase voltage relation, the first thing we need to understand is the different types of three-phase connection systems.

 

Relation Between Line Voltage and Phase Voltage in Star Connection

Consider three coils of wire or winding of a transformer attached by a common connection point. The three wires going away from each coil to the load are known as the line wires, and the conductors themselves are the phases. This system is a typical three-phase three-wire star connection system. If a neutral wire is attached to the shared middle point, then it is known as a three-phase four-wire star connection system. 

 

The terms line voltage and phase voltage has already been explained before, and they are related as follows:

 

V_line= 3–√V_phase ; 

 

While line current = phase current.

 

Relation Between Line Voltage And Phase Voltage In Delta Connection

In delta connection, all the three ends of the phases are connected to form a closed triangular loop, and it has no common neutral point as in a star connection. Here, the line and phase voltage are related as follows: 

 

V_line=V_phase; 

 

While line current = √3× phase current.

 

Difference Between Line Voltage and Phase Voltage

 

For Delta connection, the line voltage and phase voltage are equal.

 

Solved Examples

1. Calculate the phase voltage if the line voltage is 460 volts, given that the system is a three-phase balanced star connected system.

Answer: We know,

 

V_phase = V_line / √3  = 460 / √3 = 265.59 volts.

 

2. In which of the following circuit line voltage and phase voltage are equal? And what about the line voltage and phase voltage relationship in the other circuit?

Answer: As we know, in a delta connection (second figure), the line voltage and phase voltage are equal. While for a star connection line voltage is higher than phase voltage which is given by the relation: V_line = √3 V_phase.

 

Fun Facts

• In any problem or question, the voltage given is generally line voltage. In the case of phase voltage, it should be mentioned. If not mentioned, consider it as the line voltage.

• Our domestic three-phase power supply or 440 volts is the line voltage.

• The single-phase 230 volts AC supply is the voltage difference between a phase and the neutral junction or rather the phase voltage.

• The polyphase system where all the line voltages and line currents are equal is known as a three-phase balanced system. In the case of unsymmetrical loads, the system is generally an unbalanced one.

Single-Phase System 

A single-phase system is one of the most commonly used types of systems that people are familiar with. This is also what most people tend to have at their homes. For normal plugs and appliances, this type of system is used. However when it comes to needing a larger amount of power then the three-phase system is necessary. The electricity is generated by using a coil of wire which keeps on moving through the magnetic fields. As there are three coils involved the system will be called a three-phase system. Whereas when the connection is between a line and a neutral it is called a single-phase system. It is hence necessary to understand the Difference Between Line Voltage and Phase Voltage with Solved Examples via to check out the power that both systems provide.

What is the Meaning of Star Connection?

Star connection is also known as the three-phase four-wire system where there are 3 phases being involved and are connected by four wires. This is one of the most preferred systems for alternating current distribution whereas for transmission the Delta connection is used. In the star which is also denoted by Y the system of interconnection, the starting and the finishing points of the three coils are connected together to form the neutral point.

 Star connection is obtained by connecting together the similar ends of three coils which the two other ends are joined to line wires. The common point is also said to be the neutral or star point which is represented by N.

What Does Delta Connection Mean?

The Delta connection is also said to be the Mesh connection where there is the presence of three phases connected with three wires. It is also one of the most preferred AC power systems for transmission.

In simpler words, it can also be said that the three coils that are connected in series seem like they form a close mesh and when the three wires are taken out from the three junctions all the outgoing currents are assumed to be positive. It is seen that if the system is balanced then the value of the algebraic sum of all voltages within the mesh will remain zero.

Advantages of Using a Three-Phase System:

There are certain advantages of three-phase systems and can be provided as follows:

1. The three-phase currents that are present tend to cancel out each other and hence the sum will be zero making it a linear balanced load. This hence makes it possible to reduce the size of the neutral conductor as it carries little to no current.

2. Power transfer into the linear balanced load is constant and this helps in the reduction of vibrations in motor or generator applications.

3. A three-phase system will also create a rotating magnetic field that has a specific magnitude and direction allowing the design of electric motors to be simplified as no starting circuit will be needed.

Students can now also learn more about the Difference Between Line Voltage and Phase Voltage with Solved Examples via NCERT Solutions for Physics. 

The history of magnets goes back to 600 B.C. but it was only in the 20th century that scientists began to understand it and the discovery of magnets applications began.

Magnetism was most likely first discovered in a type of magnetite called lodestone, which is made up of iron oxide, a chemical compound made up of iron and oxygen. The first known users of this mineral, which they called a magnet because of its ability to attract other pieces of the same material and iron, were the ancient Greeks.

William Gilbert (1540-1603), an Englishman, was the first to use scientific methods to investigate the phenomenon of magnetism. He also found that the Earth is a weak magnet in and of itself. Carl Friedrich Gauss, a German, conducted the first theoretical studies into the nature of the Earth’s magnetism (1777-1855).

The inverse square law of force states that the attractive force between two magnetized objects is directly proportional to the product of their fields and inversely proportional to the square of the distance between them.

Quantitative studies of the history of magnetism and magnetic phenomena began in the 18th century with Frenchman Charles Coulomb (1736-1806), who developed the inverse square law of force, which states that “the attractive force between two magnetized objects is directly proportional to the product of their individual fields and inversely proportional to the square of the distance”.

Hans Christian Oersted (1777-1851), a Danish physicist, was the first to propose a link between electricity and magnetism. Experiments on the interactions of magnetic and electric fields were carried out by Frenchman Andre Marie Ampere (1775-1836) and Englishman Michael Faraday (1791-1869), but it was the Scotsman James Clerk Maxwell (1831-1879) who laid the theoretical foundation for electromagnetism in the 19th century by demonstrating that electricity and magnetism are the same things.

The work and theoretical models of two Germans, Ernest Ising (1900- ) and Werner Heisenberg (1900- ), are responsible for our current understanding of magnetism, which is based on the theory of electron motion and interactions in atoms (known as quantum electrodynamics) (1901-1976). Werner Heisenberg was a key figure in the development of modern quantum mechanics.

Origin of Magnets

Magnetism is caused by two kinds of electron motions in atoms: one is the motion of electrons in an orbit around the nucleus, which is similar to the motion of planets in our solar system around the sun, and the other is the spin of electrons around their axis, which is similar to the rotation of the Earth around its axis.

Each electron acquires a magnetic moment as a result of its orbital and spin motions, causing it to behave like a tiny magnet. The rotational force experienced by a magnet in a magnetic field of unit strength acting perpendicular to its magnetic axis defines its magnetic moment.

Because of the Pauli exclusion principle, which states that each electronic orbit can only be occupied by two electrons of opposite spin, the magnetic moment of the electrons cancels out in a large fraction of the elements. However, several so-called transition metal atoms, such as iron, cobalt, and nickel, have magnetic moments that are not cancelled, making them common magnetic materials. The magnetic moment in these transition metal elements is derived solely from the spin of the electrons.

The effect of electron orbital motion is not cancelled in the rare earth elements (which start with lanthanum in the sixth row of the Periodic Table of Elements), so both spin and orbital motion contribute to the magnetic moment. Cerium, neodymium, samarium, and europium are examples of magnetic rare earth elements.

Magnetic moments can be found in a wide range of chemical compounds containing transition and rare earth elements, in addition to metals and alloys. Metal oxides, which are chemically bonded compositions of metals with oxygen, are among the most common magnetic compounds.

According to a fundamental law of electromagnetism, a magnetic field is created by the passage of an electric current, the Earth’s geomagnetic field is the result of electric currents produced by the slow convective motion of its liquid core.

The Earth’s core, according to this model, should be electrically conductive enough to allow for the generation and transmission of an electric current. The resulting geomagnetic field will be dipolar, similar to the magnetic field produced by a conventional magnet, with lines of magnetic force lying in approximate planes passing through the geomagnetic axis.

Who was the Founder of Magnet?

Magnets make the world go-’round, and tales of their discovery and application appear to come from all corners of the globe.

Greece

Magnes, a Greek shepherd, is said to have been tending his sheep in Magnesia, a region of northern Greece, around 4,000 years ago. When he took a step forward, the nails holding his shoe together and the metal tip of his staff became stuck to the rock he was standing on! He began digging, intrigued, and found the first known lodestone. Magnesia or Magnesia was probably the inspiration for the name “magnetite” given to lodestones.

Rome

Pliny the Elder, a Roman author, and naturalist who undertook important scientific research for the then-Roman Emperor Vespasian in the early AD years described a hill made of a stone that attracted iron. Pliny attributed magnetite’s powers to magic, igniting a flurry of superstitious theories about the material, including the possibility that ships that had gone missing at sea had been drawn to magnetic islands. Pliny died in the eruption of Pompeii, which is unrelated but curious.

Scandinavia

With a large lodestone deposit in Scandinavia and insufficient light to navigate ships by during the winter, the Vikings had every incentive to put lodestone’s magnetic properties to good use. The Vikings are believed to have used a compass-like tool made of lodestone and iron as early as 1,000 B.C. Viking sailors used a magnetized iron needle inserted into a piece of straw and float in a bowl of water to signify north and south, according to legend.

China

The Chinese may have invented a mariner’s compass that was similar in construction to the Vikings’. As early as 800 A.D., the Chinese used a splinter of lodestone floating on water to navigate. Explorers such as Marco Polo brought the magnetic compass back to Italy, allowing Europeans to finally explore the oceans that the Vikings had been navigating for at least 500 years using their version of the compass.

France

One of the first written accounts of the scientific properties of magnets was authored by French scholar Petrus Peregrinus in the 1200s. The freely pivoting compass needle–a key component of the first dry compass–is depicted and discussed in his report. Peregrinus is said to have composed these works while taking part in a papal-sanctioned crusade/attack on the Italian city of Lucera.

England

William Gilbert, a physician from the United Kingdom, was the first scientist to create a magnet. He found in 1600 that magnets could be forged out of iron and that their magnetic properties could be lost when that iron was heated.

Denmark

Hans Christian Oersted began studying the relationship between electricity and magnetism two hundred years later, in 1820. He proved his theory by placing a magnetic compass near an electrical wire, which ca
used the compass’s accuracy to be thrown off.

A Brief History of Electromagnets/Electromagnetism

1770-90: Cavendish and Coulomb establish foundations of electrostatics

1820: Oersted makes the connection between flowing charge and magnetism.

1820s: Ampere identifies currents as the source of all magnetism (even permanent magnets)

1831: Faraday (also Henry) discovers that time-varying magnetic fields serve as sources for electric fields

1864: Maxwell puts it all together.

1887: Hertz demonstrates the existence of electromagnetic radiation.

History of Electromagnets

Hans Christian Orsted made an unexpected observation while preparing for an evening lecture on April 21, 1820. When the electric current from the battery he was using was turned on and off while he was setting up his materials, he noticed a compass needle deflected away from magnetic north.

This deflection convinced him that magnetic fields, like light and heat, radiate from all sides of a wire carrying an electric current, confirming the existence of a direct relationship between electricity and magnetism.

Orsted did not provide a satisfactory explanation for the phenomenon at the time of its discovery, nor did he attempt to represent it mathematically.

His discoveries sparked a wave of electrodynamics studies across the scientific community. They influenced the development of a single mathematical form to represent the magnetic forces between current-carrying conductors by French physicist André-Marie Ampère. Orsted’s discovery was also a significant step toward a unified energy concept.

One of the most important achievements of 19th-century mathematical physics is the unification, which was observed by Michael Faraday, expanded by James Clerk Maxwell, and partially reformulated by Oliver Heaviside and Heinrich Hertz. It had far-reaching implications, one of which was a better understanding of light’s nature.

William Sturgeon, an Englishman, was the first person to invent an electromagnet in 1826. It was made up of a coil that created a magnetic field when the current passed through it. There was an iron core in the coil, which increased the magnetic field and led. The magnetic field lines, in this case, are concentrated in the interior of the coil, which has the highest magnetic flux density. With a larger distance outside the coil, it decreases quickly; we can also argue that electromagnets have a large effect when used over short distances.