Category: Physics Notes PPT

Fundamental interactions, also referred to as fundamental forces in physics, are interactions that do not seem to be reducible towards more basic interactions. Fundamental interactions, also referred to as fundamental forces in physics, are interactions that do not seem to be reducible towards more basic interactions.

The gravitational and electromagnetic interactions, that produce important long-range forces whose consequences could be observed instantly in daily life, and the strong and weak interactions, that produce forces at insignificant, subatomic ranges and regulate nuclear interactions. These are the four basic interactions that are known to exist. Some scientists believe a fifth force exists, but these theories are still hypothetical.

Every known fundamental interaction could be mathematically described as a field. The curvature of spacetime, as explained by Einstein’s general theory of relativity, is responsible for the gravitational force.

The strong interaction is borne by a particle named the gluon in the Standard Model, and it is essential for quarks connecting to form hadrons like protons and neutrons. It produces the nuclear force, which binds these last particles to form atomic nuclei as a side effect. The weak interaction is borne by particles known as W and Z bosons, and this also behaves on atom nuclei, causing radioactive decay. The photon’s electromagnetic force produces electric and magnetic fields, that are necessary for the attraction amongst orbital electrons and atomic nuclei that hold atoms around each other, and also chemical bonding and electromagnetic waves, comprising visible light, and are the foundation for electrical technology.

Four Fundamental Interactions

Below given are the four fundamental interactions:-

Gravity

At the atomic level, wherein electromagnetic interactions rule, gravity is by far the poorest of the four interactions. However, the notion that gravity’s weakness could be conveniently proven by suspending a pin with a basic magnet was fundamentally flawed. Because of its proximity, the magnet is capable of holding the pin against the gravitational pull of the surface of the entire earth. There is a short distance amongst magnet and pin where a breaking point is achieved, and this distance is very short compared to Earth’s massive mass.

For two reasons, gravity is perhaps the most important of the four fundamental forces for astronomical objects travelling great distances. First, unlike strong and weak interactions and more similar to electromagnetism, gravitation does have an unlimited range of effectiveness. Second, gravity tends to show attraction and never repulsion; celestial bodies, on the other hand, tend to have a near-neutral net electric charge, in which the repulsion to one charge and the attraction from the opposite charge majorly leads to the cancellation of each other’s effect.

Even though electromagnetism is much more powerful than gravity, electrostatic attraction is irrelevant for massive celestial bodies including stars, planets, and galaxies since they have the same number of protons and electrons and therefore have a net electric charge of zero. Nothing can “cancel” gravity because it is only attractive, while electric forces can be both attractive and repulsive. All objects with mass, on the other hand, are subjected to the gravitational force that only draws. As a result, only gravitation affects the universe’s large-scale structure.

Electroweak Interaction

At low energies, electromagnetism and weak interaction fundamental forces seem to become very distinct. Two different hypotheses can be used to model them. They would combine into a single electroweak force beyond unification energy, which is on the order of 100 GeV.

The electroweak theory is crucial for modern cosmology, especially in terms of understanding how and why the universe evolved. It is because the electromagnetic and weak interaction forces of nature were still unified as a single electroweak force sometime after the Big Bang when the temperature had been above nearly 10-15K.

Sheldon Glashow, Abdus Salam, and Steven Weinberg have been granted the Nobel Prize in Physics in the year 1979 for their contributions to the merging of the weak and electromagnetic interactions between elementary particles.

Electromagnetism

The force which operates amongst electrically charged particles is known as electromagnetism. The electrostatic force operating within charged particles at rest, as well as the combined effect of magnetic and electric forces applying within the charged particles moving relative to one another, are all examples of this process.

Electromagnetism, like gravity, does have an unlimited number but is considerably greater, and thus describes a variety of macroscopic effects encountered in daily life, such as friction, lightning, rainbows, and all human-made devices that use electric current, including lasers, television, and computers.

Weak Nuclear Force Definition

Certain nuclear phenomena, including beta decay, are caused by weak interaction or weak nuclear force. As per the Weak nuclear force definition, this discovery was observed to be the very first step toward the unified theory which is referred to as the Standard Model. Electromagnetism and the weak nuclear interaction have become and are understood to be two components of a unified electroweak interaction.

1. Example of Weak Nuclear Force:

An example of weak force can be beta decay. A neutron is substituted by an electron, a proton, and a neutrino throughout beta decay.

2. Range of Weak Nuclear Force:

The range of weak nuclear force lies up to 10-17metre. The weak interaction’s efficiency is limited to a range of 10-17metre or about 1% of the circumference of a standard atomic nucleus. The weak interaction strength in radioactive decays is 100,000 times less than that of the electromagnetic force intensity.

3. The Relative Strength of Weak Nuclear Force:

The relative strength of weak nuclear force is observed to be 10-5.

Strong Interaction Force

The strong interaction force, also known as the strong nuclear force, is by far the most complex interaction due to how it differs and changes with dista
nce. The strong force is nearly undetectable at distances higher than 10 femtometers. Furthermore, it only exists within the atomic nucleus.

Just after the nucleus was identified in 1908, it was evident that the current force, presently referred also as nuclear force (strong interaction forces of nature), was required to surpass the positively charged protons’ electrostatic repulsion, a representation of electromagnetism. The nucleus would not exist if this were not the case.

The discovery of the pion in 1947 marked the beginning of the modern era of particle physics. From the 1940s to the 1960s, hundreds of hadrons were discovered, and a highly complex hypothesis of hadrons as strongly interacting particles had been established.

Geometric optics is an optical model that describes the propagation of light in terms of rays. In geometric optics, the rays of light are important to approximately determine the paths along which light propagates under certain conditions.

There are some assumptions of geometric optics, which are:

• Light rays propagate in a straight line path while traveling in a transparent medium.

• Light rays bend at the interface of two with different refractive indexes. Light rays also split under certain circumstances.

• Light rays follow a curved path in a medium of changing refractive index.

• Light rays can be absorbed, reflected, and refracted.

Light Geometric Optics cannot explain the properties of light like diffraction and interference. This simplification is useful in practice. 

Light Geometric Optics is an excellent way to describe the behavior of light as its wavelength is extremely small as compared to the size of the object that light deals with.

The Geometric Optics is significantly useful to describe the geometric aspects of imaging like optical aberrations.

What is Geometric Optics?

Light can behave in many ways as it has dual nature. It has wave nature and also particle nature in the form of a photon. 

Light travels in a straightline & this property of light is called rectilinear propagation of light. Geometrical optics primarily deals with the rectilinear propagation of light and phenomena like reflection, refraction, and polarization.

Geometrical optics is also called ray optics. It is a model of optics that describes the rectilinear propagation of light in terms of rays. In geometric optics, the path of the propagation of light in a straight line is determined by studying the rays of light.

For convenience, optics is divided into two sections based on the size of the objects with which light interacts. When light interacts with an object that has a wavelength much greater than the wavelength of light, then the behavior of light is like that of a ray, and it doesn’t display its wave nature. This is the part of optics, which is called “geometric optics”.

Refraction of Light Through a Prism Experiment

Our Objective

1. To study the angle of deviation ‘d’, and find the angle of minimum deviation ‘D’ from the i-d curve for an angle of incidence ‘i’.

2. To find the refractive index of the material of prism by using A (angle of the prism) and D.

Theory

Prism

A prism is an optical device. It is made up of polished flat surfaces that refract light. A prism that has a triangular base and rectangular sides is called a triangular prism.

A prism is usually made from materials like glass, plastic, and fluorite. A prism is used to split white light into its constituent components.

How a Prism Works?

When there is a transaction of light from one medium to another medium, it gets refracted by an angle. The angle of refraction of light depends on the angle of incidence, which the incident ray makes with the surface of the prism, and it also depends on the ratio between the refractive indices of the two media. 

This is called Snell’s law and is given by:

n = sin i/sin r                           

Where,

i = angle of incidence

n = refractive index of the material of the prism

r = angle of refraction.

Different wavelengths of light refract differently, and the refractive index varies with the wavelength of light used. Light of different color (or wavelength) refract differently and emerge from the prism with different angles. This is called dispersion. 

This property is that light can be used to separate a single beam of light into its constituent colors.

The relation between Refractive Index ‘n’, Angle of Minimum Deviation ‘D’ and Angle of Prism ‘A’ can be learned here below:

Consider the following triangular prism.

The two refractive surfaces of the given prism are ABFE and ACDE, respectively. The angle between them, angle ‘A’ is the angle of the prism.

A ray of light through prism undergoes two refractions while passing through the prism. 

Let KL be a monochromatic beam of light that falls on the side AB of the prism. It gets refracted traveling along the path LM. At the point M it undergoes refraction once again and emerges out along MN. 

The angle of deviation can be stated as the angle where the emergent ray deviates from the extending direction of the incident ray.

If there is a rise in the angle of incidence, then the angle of deviation ‘d’ decreases and reaches a minimum value. 

The angle of deviation increases if the angle of incidence is further increased.

A graph is drawn by taking the angle of incidence ‘i’ in the X-axis, and the angle of deviation ‘d’ along the Y-axis. 

The graph obtained is a curved graph.

The angle of minimum deviation is calculated from the graph. Let D be the angle of minimum deviation. The refractive index ‘n’ of the material of prism is calculated by using the formula.

N = (sin (A+D)/2)/sin A/2

Do You Know?

Do you know what relative refractive index is?

The relative refractive index can be defined as the ratio of the speed of light in one medium to that of the speed of light in another medium.

The high-frequency oscillation of the electric current that is flowing through the semiconducting solids is known as the Gunn effect. This is used in a solid-state device called Gunn diode in the production of short radio waves called microwaves. In the early 1960s, it was discovered by J.B.Gunn. The materials such as gallium arsenide or cadmium sulfide can exhibit the Gunn effect in such types of materials the electrons can exist in two states of mobility. The electrons that have a higher mobility rate can move through the solids easily than those electrons that have a lower mobility rate. In the absence of electrical voltage, the electrons are in a high mobility state. When the voltage has applied the electrons just as in the conductors they start to move. This motion of electrons can cause an electric current. In the case of some solids, if the voltage applied is more then the movement of electrons increases and thus the increase in the flow of current. In the materials that exhibit the Gunn effect, the strong electrical voltage can make the electrons move into a lower mobility state. This makes the electrons move slowly and thus decreases the electric conductivity. In electric circuits such as the Gunn diode, the relation between the voltage and current can result in the generation of high-frequency AC from the direct source. 

Gunn Diode

Gunn diode is a form of the two-terminal semiconductor electronic component that is used in high-frequency electronics and has negative resistance. It is also known as TED (Transferred Electron Device). It is discovered by J.B. Gunn depending on the Gunn effect in 1962. It is used in oscillators in the generation of microwaves whose application is found in automatic door openers, radar seed guns, and microwave relay data transmitters. 

The internal construction of these diodes is different from the other diodes where it consists of only N-doped semiconductor and most of the diodes consist of N and P-doped regions. Like other diodes, it cannot conduct in one direction and it cannot rectify the alternating current that’s why the term TED. There are three regions present in the Gunn diode: two of these regions are doped heavily on each terminal and a thin layer is present in between these two layers that are made of n-doped material which is light. The electrical gradient will be more across this thin layer when the voltage is applied to the device. The current in the middle layer will increase when the voltage is increased and when the high-field values the middle layer conductive properties are altered thus the resistivity increases and the current will fall. By this, we can tell that the Gunn diode has a region known as negative resistance in the curve of current versus voltage where the increased voltage value can cause a decrease in the current flow. This is the property used to amplify the radio frequency or it can become unstable and it oscillates when it is biased. 

Working of Gunn Diode

In some of the semiconductor materials such as Gallium arsenide (GaAs), the electronic band structure of these materials consists of valence and conduction bands along with these bands there is another energy band or sub-band. Compared to the conduction band, this third band is at higher energy and it is empty until the energy is passed to it to promote the electrons. This energy is obtained from the kinetic energy of the ballistic electrons. These are the electrons that are present in the conduction band but are moving with some kinetic energy and are capable of moving to the third band. These electrons are either injected by a cathode with energy or they start below the Fermi level by applying strong energy; they are provided with a long mean free path to obtain the needed energy. With the application of forwarding voltage, the Fermi level present in the cathode moves to the third band and by matching the density of states and by the usage of additional interface layers the reflections of ballistic electrons starting around the Fermi level will be minimized.

In GaAs, the effective mass of the electrons that are present in the third band is said to be higher than that of the conduction band. Thus the drift velocity or mobility of the electrons present in that band is less. By increasing the forward voltage, the number of electrons that reach the third band will increase thus it slows down the movement this, in turn, leads to the decrease in the current. This cause can create negative differential resistance. 

The charge carrier density that is present along the cathode becomes unstable and develops the small segments that are of low conductivity by the application of a high potential to the diode and the remaining cathode portion will have high conductivity. The cathode voltage drops will occur along the segment having a high electric field region. By the influence of this electric field, these segments will move from cathode to anode. There will always be a thin slice of high field strength that is present at the background of the low field strength thus it is difficult to balance the population of both bands. A low conductive region is formed at the cathode by the small increase in the forward voltage and due to the increase in the resistance this segment moves along the side of the bar to reach the anode. When the segment reaches the anode, it is absorbed to form a new segment in the cathode by maintaining the constant voltage. Any existing slice will be quenched by decreasing the resistance if the voltage is decreased.

Application of Gunn Diode

Let us take a look at the various application of Gunn diode. These Gunn diodes are mainly used at the frequency of microwave or above that due to their capability of high frequency. They can produce the highest output powers of the semiconductor devices and are commonly found using the oscillator. They are also used in microwave amplifiers to amplify the signals.

• Sensors and Measuring Devices: The Gunn diode oscillators are used in the generation of microwave power for applications such as airborne collision avoidance radar, sensors to monitor the flow of traffic, anti-lock brakes, car radar detectors, automatic door openers, burglar alarms, motion detectors, pedestrian safety devices, sensors to avoid derailment of trains, moisture content monitors, and remote vibration detectors. 

• Radio Amateur Use: By the virtue of low voltage operation these Gunn diodes serve as generators of microwave frequency for the low power microwave transceivers these are called Gunnplexers. These were first used in the late 1970s by the British amateur radio and many designs of these Gunnplexers are published in journals. The diode is mounted into the three-inch waveguide and to drive the diode it is approximately modulated with the supply of low voltage say less than 12v power supply of direct current is used. One end of the waveguide is fed to the horn antenna and another end is blocked to form a resonant cavity. 

To enable the listening of the other amateur stations an additional mixer diode is inserted into the waveguide and is often connected to a modified FM broadcast receiver. These are commonly used in the frequency range of 10 GHz and 24 GHz ham bands and sometimes 22 GHz security bands are modified to use as diodes. Typically if the mixed diode is reused i
n the existing waveguide then these parts are known for their static sensitivity. Commercially this part is protected with the parallel resistor and a variant is being used in the Rb atomic clocks. Even the Gunn diode is weakened for the usage the mixer diode is used for the applications of lower frequency. 

• Radio Astronomy: For milli-meter and sub-milli-meter wave radio astronomy transmitters, these Gun oscillators are used as the local oscillators. The Gunn diode is mounted in such a way that the cavity is tuned to resonate at the rate of twice the fundamental frequency of the diode. By adjusting the micrometre the cavity length is changed. Over a tuning range of 50%, these Gunn diodes are capable of generating power over 50mW. For the application of the sub-milli-meter wave radio astronomy transmitter, the Gunn oscillator frequency is multiplied by the diode frequency.

Conclusion

Gunn diodes are mainly used at the range of microwave frequencies or above due to their capability of high frequency. The Gunn diodes are usually built to generate the microwave frequencies at the range of 10 GHz to THz. Gunn diode semiconductor material is GaAs. The other material used is Ge, InAs, ZnSe, CdTe and many more. In electric circuits such as the Gunn diode, the relation between the voltage and current can result in the generation of high-frequency AC from the direct source. The advantage of these is high bandwidth, high reliability, the manufacturing cost is low, the operating voltage is relatively low, etc. 

The Helmholtz equation is named after a German physicist and physician named Hermann von Helmholtz, the original name Hermann Ludwig Ferdinand Helmholtz.This equation corresponds to the linear partial differential equation: where ⛛² is the Laplacian, is the eigenvalue, and A is the eigenfunction.In mathematics, the eigenvalue problem for the Laplace operator is called the Helmholtz equation. That’s why it is also called an eigenvalue equation.

Here, we have three functions namely:

The relation between these functions is given by:

Here, in the case of usual waves, k corresponds to the eigenvalue and A to the eigenfunction which simply represents the amplitude.

Helmholtz’s free energy is used to calculate the work function of a closed thermodynamic system at constant temperature and constant volume. It is mostly denoted by (f). 

The formula for Helmohtlz free energy can be written as :

                       F = U – TS

• Where F = the helmholtz free energy. It is sometimes denoted as A.

• U = internal energy of the system

• T= The absolute temperature of the surrounding area.

• S= Entropy of the given system.

In contrast to this particular free energy, there is another free energy which is known as Gibbs free energy.

Gibbs free energy can be defined as a thermodynamic potential that is used under constant pressure conditions. 

The equation of the Gibbs free energy is described as 

                      ∆G= ∆H – T∆S

• ∆G = change in Gibbs free energy in a system

• T = the absolute temperature of the temperature.

• ∆S = change in entropy of a system.

• ∆H = change in the enthalpy of a system.

Helmholtz Equation Derivation

The wave equation is given by,

Separating the variables, we get, u(r , t) = A(r) T(t)…(2)

Now substituting (2) in (1):  

Here, the expression on LHs depends on r.  While the expression on RHS depends on t.These two equations are valid only if both sides are equal to some constant value. On solving linear partial differential equations by separation of variables. We obtained two equations i.e., one for A (r)  and the other for T(t).

Hence, we have obtained the Helmholtz equation where – is a separation constant.      

Helmholtz Free Energy Equation Derivation

Helmholtz function is given by,

 F = U – TS

Here, 

U = Internal energy

T = Temperature

S = Entropy

F_i is the initial helmholtz function and F_r being the final function.

During the isothermal (constant temperature) reversible process,  work done will be:                    

W   ≤    F_i – F_r

This statement says that the helmholtz function gets converted to the work. That’s why this function is also called free energy in thermodynamics.

Derivation:

Let’s say an isolated system acquires a δQ heat from surroundings, while the temperature remains constant. So, Entropy gained by the system = dS

Entropy lost by surroundings = δQ/T

Acc to 2^nd law of thermodynamics, net entropy =  positive

From Classius inequality:                                

dS – δQ/T ≥ 0                               

dS  ≥ δQ/T

Multiplying by T both the sides, we get                      

 TdS  ≥  δQ

Now putting  

δQ = dU + δW (1^st law of thermodynamics)                 

TdS ≥ (dU + δW)

Now,    TdS ≥  dU + δW       Or,     δW   ≤ TdS – dU           

Integrating both the sides:  

           

w S_r U_r [int] δW ≤ T[int]dS – [int] dU 0 S_i U_i W ≤ T (S_r – S_i) – (U_r – U_i) W ≤ (U_i – TS_i) – (U_r – TS_r)

Now, if we observe the equation.  The terms  (U_i – TS_i) and (U_r – TS_r) are the initial and the final Helmholtz functions.Therefore, we can say that: W  ≤    F_i – F_r

By whatever magnitude the Helmholtz function is reduced, gets converted to work.

Applications:

The application of Helmholtz’s equation is researching explosives. It is very well known that explosive reactions take place due to their ability to induce pressure. Helmholtz’s free energy helps to predict the fundamental equation of the state of pure substances. This is the main application of Helmholtz’s free energy.

Apart from the described application above, there are some other applications also with Helmholtz energy shares. This can be listed as written below:

Helmholtz’s free energy equation is highly used in refrigerators as it is able to predict pure substances. So these are highly used for industrial applications.

Helmholtz’s free energy is also very helpful to encode data. Due to its ability to analyze so precisely, it acts as a wonderful autoencoder in artificial neural networks. It proves helpful in the calculation of total code codes and reconstructed codes.

Points to Remember about Helmohtlz Free Energy:

• Internal energy, enthalpy, Gibbs free energy, and Helmholtz’s free energy are thermodynamically potential.

• No more work can be done once Helmholtz’s free ener
  gy reaches its lowest point.

Helmholtz Equation Thermodynamics

The Gibbs-Helmholtz equation is a thermodynamic equation. This equation was named after Josiah Willard Gibbs and Hermann von Helmholtz. This equation is used for calculating the changes in Gibbs energy of a system as a function of temperature. Gibbs free energy is a function of temperature and pressure given by,

Applications of Helmholtz Equation

There are various applications where the helmholtz equation is found to be important. They are hereunder:

• Seismology:  For the scientific study of earthquakes and its propagating elastic waves.

• Tsunamis

• Volcanic eruptions

• Medical imaging

• Electromagnetism: In the science of optics, the Gibbs-Helmholtz equation: Is used in the calculation of change in enthalpy using change in Gibbs energy when the temperature is varied at constant pressure.

This method is used for reconstructing acoustic radiation from an arbitrary object.

Do you know what is a lifter? A lifter is something that carries heavy loads. It works on the principle of Pascal’s law. A simple lifter is a hydraulic lifter and is one of the commonly known lifters. 

You must have observed a balloon and an airplane flying even if there’s a weight difference. So, what lifts them up? Also, you might’ve seen a lifter in service centres and garages. You feel enthusiastic to build the same device.

If you are the one looking for an effortless and interesting technique to build the same, keep scrolling this page.

How to Make a Lifter?

In making a lifter, we will use the following household items:

Steps to Make a Lifter

• Cut an indexed board wider by 1/3rd, while keeping the longer side the same size as that of the object to be lifted. A lifer with a width of 0.25 inches and a length of 1 inch would be enough for a 0.75 round table.

• Now, fold the strip of paper to make it of the shape of an alphabet ‘N’ 

• Apply fevicol on one side of the paper lifter and attach the end with the fevicol cover against the backend of the diagram where the picture would be placed for raising.

• Now, attach the label to another part of the lifter of paper. If the object attached does not possess a label with a sticky part, try using fevicol to secure it at the lifter end.

Concept of a Lift

Let’s hold a spoon in one hand and a balloon in the other. Release your hands and you observe that the balloon rises up and the spoon falls.  Similarly, if you take a pan of millions of spoons and consider an airplane. The airplane flies while spoons remain as such. So, why is there a difference between these two scenarios?

Well, in a balloon and an airplane, there’s something called Dynamic lift that lifts these two up.

In an airplane, four types of forces are acting on it, the lower one is weight, the upper one is a lift, the forward force is thrust and the backward is a drag.

When the engine’s thrust pushes the airplane forward, the drag pulls it backwards and when the lift pulls it up, the weight of an airplane pulls it down. Since the pressure at the upper end, is higher and that at the lower side is low, this pressure difference between the two ends creates an effective upward force, which is a dynamic lift that lifts the plane up.

So this was the case for an object flying in the sky. Now, let’s discuss what do hydraulic lifters do?

What is a Hydraulic Lifter?

A hydraulic lifter is of two types viz: hydraulic flat tappet lifter and hydraulic roller lifter. A flat lifter looks flat at the bottom and the roller lifter comprises rollers at the bottom, as you can see in two images below:

     (Image to be added soon)                   (Image to be added soon)                  

                 Flat lifter                                                   Roller lifter

A roller lifter is greater in height than a flat lifter. A roller is preferred to a flat lifter in the following ways:

• Though it is costly, i.e., about 7-8 mn dollars but it produces more horsepower than the standard or a flat lifter.

• Rollers at the bottom produce less friction because when they roll on the camshaft, there’s no resistance, so more durability of lifters.

A hydraulic lifter works on the phenomenon of Pascal’s law. You can see a simple diagram of a hydraulic lifter below:

                           (Image to be added soon)

This hydraulic lift is found in service centres, where servicemen lift the car up for repairing. Here, you can see two cylinders connected to each other with a pipe. These two cylinders bear differing cross-sectional areas and each of these is provided with an airtight frictionless piston. 

Let A1, A2 be the cross-sectional areas of two pistons held at the top of these two cylinders, respectively, where A2 >> A1, as we can see that the piston on the left-hand side bears a smaller area as compared to that on the right-hand side.

(Image to be added soon)

Now, these cylinders are filled with an incompressible liquid, as you can in the image below:

(Image to be added soon)

The downward force applied on the left piston is F1 and the pressure exerted on it is:

P = F1/A1

Now, according to Pascal’s law, this pressure is equally transmitted to the small piston of the cylinder on the RHS, so the pressure exerted on it will be:

P = Fg/A2

Since A2 >> A1, therefore Fg > F1.

It means that the force applied to the smaller piston appears as a very large force on the large one. As a result of this heavy load like a car or a motorbike placed on the larger piston is easily lifted upwards.

Conventional sources of energy are the energy that is naturally available in nature. They are present in a minimal amount in the world, and will one day perish if it is not sustainably used. Natural gas, coal, oil, thermal power plants, hydroelectricity, and hydropower plants are some of the examples of conventional sources of energy. Among these sources, hydroelectricity is considered to be clean and an efficient source of energy for long term use.

 

The most significant disadvantage of conventional sources of energy is that they tend to pollute the environment. They are also very limited and finite in terms of quantity available for extraction. The only exception is hydroelectricity. India has a high potential to produce electricity with hydropower plants. Only 15% of the total open source is being used right now. Therefore, you need to get a proper grasp on what is hydroelectricity and on what is hydropower plant.

 

Hydroelectricity

Let’s start by answering the question of what is hydroelectricity. When electrical current is generated from the kinetic energy of flowing water, we call it hydroelectricity. It could be a water turbine driven electric generator in a dam, a generator driven by a water wheel in a water stream, or even an air-driven electric generator in which air is compressed to drive the generator by the action of ocean waves.

 

Advantages of Hydroelectricity:

• It is a clean and non-polluting source of energy.

• No fuel is required. Water is the source of energy, and it does not consume water.

• Dams are constructed near rivers. As the water level rises, the kinetic energy of water gets changed to potential energy.

 

Disadvantages of Hydroelectricity:

 

Uses of Hydroelectricity:

 

Hydropower Plant

Let’s try to understand what is hydropower plant. When water is at a height, it has potential energy stored in it. When this water flows down, its potential energy is first converted to kinetic energy and then to mechanical energy with the help of turbines. With the use of a generator, the mechanical energy is transformed into electrical energy. Hydropower is essential only next to thermal power. Hydropower plants meet nearly 20% of the total power of the world.

 

Advantages of Hydropower Plants:

• Rainwater is stored in the dam. Thus, it is considered to be a renewable source of energy.

• The construction of dams helps in providing irrigation of the local farmers; it also helps in controlling floods.

• This method of electricity generation does not produce any pollution.

• Their operational cost is very low.

 

The Disadvantage of Hydropower Plants:

• Hydropower plants require high capital with a low rate of return.

• Dams can only be built at specific locations.

• A Large area of agriculture is submerged underwater.

 

Uses of Hydropower Plants:

• Since the generation of electricity in hydropower plants is very quick, they can provide essential back-up power during major electricity outages.

• Hydropower is used to control flood, help in irrigation, and water supply.

• Hydropower plays a major role in reducing greenhouse gas emissions.

 

Working Principle of Hydropower Plant

Now that you have a thorough understanding of what is hydroelectricity, and on what is hydropower plant, we will soon see how is hydroelectricity produced in the plants. We use the gravitational force of the water to produce electricity. 

 

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The first thing that we need is a high-rise dam to stop the flow of water and accumulate it in one place. When all the water is gathered, a lot of potential energy is stored in the water. Next, the sluice gates are opened up, and the water is made to flow with high pressure. When water flows, the potential energy gets converted into kinetic energy. When the running water hits the blades of a turbine, the kinetic energy of the water is converted into mechanical energy. This turbine is in turn connected to a generator. As the turbine rotates rapidly, the generator generates electricity in the powerhouse. The used water will flow out into the river, and the water level in the dam decreases. This level will increase once again with the help of natural rainwater. Therefore, it is a natural resource that will never get exhausted.

 

World Distribution of Hydropower

The most crucial and widely used renewable source of energy is hydroelectricity which is produced in hydropower plants. Hydropower plants meet only 20% of the total power of the world. When it comes to the production of hydroelectricity, China is the largest producer, followed by the United States, Brazil, and Canada. Around 66% of the economically feasible hydropower is yet to be tapped. Untapped resources are still present in Central Africa, China, India, and Latin America.

• Hydropower remains the dominant electricity source across North and Central America.

• South America was the second-fastest-growing region, adding 4,855 MW in installed hydropower capacity in 2018.

• Hydropower is increasingly recognised in Europe for its flexible services to maintain secure, affordable and sustainable energy supply

• East Asia and the Pacific again saw the highest annual increase in hydropower installed capacity in 2018.