Category: Physics Notes PPT

A line of Force can be defined as a way or path, be it straight or curved, and the tangent at any given point to it gives the direction of the electric field intensity at that point. The conception of electric lines of forces was founded by Michael Faraday in the year 1837. A force is experienced when a unit charge or point charge is placed in the electric field of another charged particle. The direction of this force can be represented by the imaginary lines, which are called electric lines of force. Electric lines of force are also known as electric field lines.

In Physics, lines of force are the path followed by an electric charge. They are free to move in an electric field or a mass free to move in a gravitational field. Lines of force are lines in any source field, where the tangent drawn at any point gives the field direction at that point and the density of that gives the magnitude of the field. 

The concept of lines of force was introduced in the 1830s by the English scientist Michael Friday. Here we will discuss magnetic lines of force as well as electric lines of force and their properties.

In physics, lines of force are the imaginary line that represents a field of force, such as an electric or magnetic field.  If we draw a tangent at any point on the lines of force gives the direction of the field vector at that point.

Magnetic Lines of Force

Since no isolated unit pole has ever been discovered in the case of a magnetic field, the field lines are called lines of force only. An electric charge that travels along a magnetic field line undergoes no magnetic force.

Properties of Lines of Force 

Below we have discussed the properties of magnetic lines of force:

• Magnetic lines of forces always emerge from the north pole and it merges at the south pole.

• As the distance between the poles increases, the density of magnetic lines also decreases.

• The direction of field lines inside the magnet starts from the South Pole and ends at the North Pole.

• Two magnetic lines of force can never intersect each other at any point.

• The strength of the magnetic lines of force is similar throughout the magnetic field and it is proportional to how close the lines of force are.

Force Line

Force lines are a technique that we use in solid mechanics for the visualization of internal forces in a deformed body. A forced line graphically represents the internal force that is acting within a body across imaginary internal surfaces. These lines of forces show the internal forces and their directions.

Important Characteristics of Electric Lines of Force

• They contract longitudinally.

• Electric lines of force expand laterally.

• They cannot intersect with each other.

• Two electric lines of force travelling in the opposite direction attract each other.

• Two electric lines of force travelling in the same direction repel each other.

• The lines of force are imaginary but the field it represents is real.

• There are no lines of force inside the conductor.

Electric Lines of Force 

Electric Lines of Force Definition – Electric field lines are the way of visualizing electric fields. Electrical lines of force are described as a way or path. It can be straight or curved lines so that the tangent gives the direction of the intensity of the electric field at that point.

An electric line of force is an imaginary line that is a continuous line or curve that we draw in an electric field such that tangent to it at any point gives the direction of the electric lines of force at that point. The direction of a line of force is in the direction where a small free positive charge will move along the line. It always travels from positive charge to negative charge.

The electric lines of force represent the field of a positive electric charge in space.  It consists of a family of straight lines that radiate uniformly in all directions from where the charge originates. A second positive charge is placed in the field that will travel radially away from the first charge.

Properties of Electric Field Lines

• The field lines never intersect each other.

• Electric lines of force contract longitudinally.

• They expand laterally.

• The magnitude of charge and the number of field lines, both are proportional to each other.

• The starting point of the field lines is at the positive charge and the ending point is at the negative charge.

• A single charge must be used for the field lines that either start or end at infinity.

Properties of Electric Lines of Force

• Each electric line of force is conceptually imagined; it does not have any physical existence.

• The total number of lines of force that emerges from a charged body is equal to the charge of the body measured in Coulomb.

• Each electric line of force originates from the positive charge and is terminated to the negative charge.

• A tangent drawn at any point on an electric line of force indicates the direction of the electric field lines at that point in the field.

• Each electric line of force emerges normally from the surface of the charged body.

• Electric lines of force contract only longitudinally.

• Electric lines of force can expand laterally.

• There are no two electric lines of force crossing each other.

• In the same direction, the electric lines of force repel each other.

• The electric lines of force in opposite directions attract each other.

• No lines of force can exist inside the conductor.

Opposite Charges Attract

If two opposite charges placed close to each other get attracted. This is because the force present between them is attractive. If we consider two opposite charges, positive and negative. Then, for positive charge, the electric lines of force move away from the centre of positive charge and for a negative charge, the electric lines of force move towards the centre of the negative charge.

Like Charges Repel

Two positive charges move in the electric lines of force when both the forces are positioned close to each other, both the charges will try to move in the direction of electric lines of force. It is observed that the positive charge at the left side will try to move towards the positive charge at the right side, whereas the electric lines of force of the right side’s positive charge oppose this movement. 

In a similar way, the positive charge at the right side will also experience an opposing force from the left side’s positive charge. Therefore, both the charges, positive charge and negative charge will have a repulsive force from each other.

Difference between Magnetic and Electric Lines of Force

The differences between magnetic and electric lines of force are given below:

Magnetic Lines of Force

1. It is always in a close loop.

2. Magnetic lines of force can pass through iron more easily as compared to air.

3. Outside the body of the magnet, the direction of magnetic field lines is from the north pole to the south pole.

4. Magnetic fields formed from the motion of the charge, or the current.

Electric Lines of Force 

1. They never form a close loop.

2. Electron moves from positive to negative 

3. They have a static charge.

4. Electric fields are the result of the strength of the charge.

Line of Force Examples

1. If p and p’ make angles 0 and 0 with the axis, then the equation to a line of force is cos 0 – cos B’= constant. 

2. A line of force is considered as proceeding from the north pole towards the south pole of the magnet, its direction being that in which an isolated north pole would be urged along with FIG.

3. The resultant magnetic force at every point is in the direction of the normal (n) to the surface. Hence, cut the equipotential surfaces at right angles.

However, the magnetic influence itself is entirely invisible, its existence and strength can be judged by such lines of force which indicate the direction in which the magnetic influence is acting. The intensity of the field at any point can be achieved by the density of the electric lines of force at that point. 

When two opposite charges are placed close to each other, the electric lines of force present between them will become shorter in length. When two similar charges are placed closer to each other, the length of electric lines of force present between those charges will enlarge.

Luminous Intensity is a measure of the wavelength-weighted power radiated by a light source in a particular direction per unit solid angle. It is based on the luminosity function, a standard model of the sensitivity of the human eye. The SI unit of luminous intensity is the candela or cd, it is an SI base unit.

 

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Contents

In this article, we will learn about the following topics in detail:

1. luminous intensity meaning

2. The unit of luminous intensity

3. Luminous intensity definition

4. SI unit of luminous flux

 

Luminous Intensity

Luminous intensity is an expression that describes the amount of light power emitting from a point source within a solid angle of one steradian. 

 

For instance, a frequency of 540 terahertz, i.e., 540 THz or 5.40 x 10¹⁴Hz is specified. Here,  A frequency of 540 THz corresponds to a wavelength of about 555 nanometers (nm), which is in the middle of the visible light spectrum and is usually accepted and the human eye is sensitive to this wavelength. 

 

The quantities employed to express luminous intensity are obvious to most non-scientists.

 

A steradian is the standard unit of the solid angle; a sphere encloses 4 p, which is approximately equal to 12.57 steradians.

 

Luminous intensity can be used as a factor to determine the quantify the power emitted by any light source in a particular direction for a given unit solid angle. The luminosity function provides a standardized model to determine the sensitivity level of the human eye. In the SI unit system, luminous intensity is represented as candela (cd). It is defined as the quantity of visible light that is emitted by a source in a unit time per unit solid angle. Lumens are used to characterize the luminous flux from power a source at any second. The lumens value mentioned is used as a reference to visual sensation to light.

Unit of Light Intensity

Luminous intensity is symbolized as LV. I the SI system, the unit of  luminous intensity is Candela or Cd; however, we have two more units of luminous intensity; these are as follows:

• Steradian

• Hefner Kerze

• Candlepower

 

Luminous Intensity Definition

For understanding the luminous intensity definition; let’s look at the history of luminous intensity:

 

Decades ago, the luminous intensity was measured in the form of a unit called the candle. This expression came from the fact that one candle represented on average the amount of visible radiation emitted by a candle flame. 

 

This was an inexact description because burning candles vary in brightness. So, for a time, a specified amount of radiation from the element, say, platinum at its freezing temperature was used as the standard. 

 

Then in the late 20th century, the candela was introduced and this unit was adopted as the standard unit of luminous intensity. 

 

One Candela

One candela or 1 cd is the magnitude of an electromagnetic field or  EM-field in a certain direction that has a power level equivalent to a visible-light field of 1/683 watt 1.46 x 10⁻³ Watt per steradian at 540 THz.

 

Here, we also discussed the luminous flux. So, luminous flux is the amount of electromagnetic radiation emitted by any source. The SI unit of luminous flux is Lumen.

 

Luminous Flux

The luminous flux tells us how much light is emitted by any light-emitting source. This refers to lights in a visible band emitted by the LED lamp in all directions. The physical unit for the luminous flux is called lumen and an acronym for lm. With the old light-emitting sources, the brightness/sharpness could be compared well on the basis of the wattage.

 

Unit of Luminous Intensity

• The SI unit of luminous flux is the lumen or simply lm.

• Till 19 May 2019, we used to define one lumen as the luminous flux of light produced by a light source that emits one candela of luminous intensity over a solid angle of one steradian. 

• Then on 20 May 2019, the lumen was defined by fixing the luminous efficacy of monochromatic radiation of frequency 540 × 10¹² Hz (green light) to be 683 lm W^-1.

• In other systems of units, luminous flux also has units of power.

 

Luminous in Photometry

In photometry, luminous flux or luminous power is the measure of the received power of light. It varies from the radiant flux, i.e., the measure of the total power of electromagnetic radiation including infrared (IR), ultraviolet (UV), and visible light, in that case, luminous flux is adjusted to reflect/emit the varying sensitivity of the human eye to varying wavelengths of light.

 

Luminous Efficacy

The luminous flux takes into account the sensitivity of the eye by weighting the power at each wavelength with the luminosity function, which represents the response of the eye to different wavelengths. 

 

The luminous flux is a weighted total of the power at all wavelengths coming in the visible band. The light outside the visible band does not contribute to brightness. So, the ratio of the total luminous flux to the radiant flux is known as the luminous efficacy.

Physics and Its Importance

Physics plays a vital role by being a branch of science that deals with the structure of matter that helps in studying various things and how they actually work and thereby finding out how these fundamental constituents interact with various elements in the universe. It starts from the study of objects starting from the very small ones using quantum physics to the entire universe using the various general theory of relativity. It is indeed these physical processes and phenomena of a given system based on the physical characteristics, the composition of any matter that is found.

Physics plays a vital role in acting as an international enterprise, which plays a key role in the progression of humankind in a futuristic way by studying how the various components and elements of the universe actually function and interact with each other and various systems. This important aspect of Physics plays a vital role in ensuring that it adds valuable contributions to the technological infrastructure and provides trained professionals and profound scientists to the universe, necessary to create significant scientific advances and help us discover our future with
a noble mission to ensure that the earth is transformed into a better place to live in.

A sub-discipline of physics in the field of electromagnetism is the magnetic flux through a surface, which refers to the surface integral of the magnetic field’s (B) normal component passing through that surface. To be specific, magnetic flux is defined as the number of magnetic field lines passing through a given closed surface. In this particular scenario, the area under consideration can be in any orientation corresponding to the direction of the magnetic field and of any size.

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Symbol and Formula of Magnetic Flux

Magnetic flux are denoted by the Greek letter Phi and have the symbol [Phi  or Phi _{B}]. 

To calculate the magnetic flux, we can use the formula given below:

[ Phi _{B} = B. A = B A cos Phi ]

Where, 

[ Phi _{B} ]  = Magnetic Flux

B = Magnetic Field

A = Area

[ Phi ] = Angle at which the magnetic field lines pass through the given surface area

Fluxmeter is used to measure the magnetic flux. 

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SI Unit of Magnetic Flux 

Weber (Wb) is the SI unit of magnetic flux, which is named after Wilhelm Eduard Weber, a German physicist. A flux density of one Weber per square meter or [Wb/m^{2}] is one Tesla, denoted by T (explained in the next section). Quite often, Weber is expressed in a multitude of other units, as shown below:

[Wb = kg m^{2}/s^{2} A = V.s = H.A = T.m^{2} = J/A = 10^{8}Mx]

Where, Wb = Weber, T = Tesla, V = volt, m = metre, J = joule, s = second, H = Henry, A = ampere, and Mx = Maxwell.

 

CGS unit of Magnetic Flux

The CGS unit of magnetic flux is Maxwell (Mx) or Abweber (abWb).

Fundamental Unit of Magnetic Flux

The fundamental unit of magnetic flux is Volt-seconds.

Understanding the Term Magnetic Flux Density

The force acting per unit length on a wire placed perpendicular (at right angles) to the magnetic field per unit current is the magnetic flux density (B).

•  Tesla (T) or [ Kg s^{-2} A^{-1}] is the SI unit of magnetic flux density (B).

•  The magnetic flux density, denoted by the symbol B, is a vector quantity

• The CGS unit of magnetic flux density is Gauss, which is abbreviated as G or Gs

The formula for calculating the magnetic flux density is as follows:

B = F/I L

Where

F = total force acting on the wire

I = current flowing through the wire

L = length of the wire

Submultiples of Weber(Wb)

Multiples of Weber 

Magnetic Flux

It can be defined as the total number of magnetic field lines which pass through a given closed surface. This quantity provides a measurement for the total magnetic field in a given area. The areas we take into consideration are of different sizes and different orientations considering the magnetic field direction. It is generally measured using a flux meter. There are different units for flux. In the SI unit, it is Weber which is abbreviated as Wb. The CGS unit that is used for this is Maxwell and the unit used fundamentally is Volt-Seconds. Thus, it is a measurement of the total magnetic field that passes through an area we take into consideration. It is a very good tool that can be used for finding the magnetic force on an area. It is related to the area chosen and we can choose an area of any size and arrange it according to the magnetic field.

Faraday conducted his experiment on electromagnetic induction and gave insights on the mathematical relation related to it. He made many contributions to science and was known greatly in the [19^{th}] century for his scientific contributions. Magnetic flux plays a major role in the process of electromagnetic induction. In order to calculate this quantity, we take into consideration the field-line image of a magnet or many magnets present.

The population is one of the most talked-about subjects in the current world. Every nation is worried and is working towards the benefit of its population. The population of any country has the potential of making the country more successful and taking it to greater heights of achievements. The quality of the population is the country’s way of proving to the world how many people can develop into world leaders of tomorrow. India is one of the fastest-growing countries in terms of population has the same kind of scenario going around all over.

The population of India is also the biggest asset for the country as a whole. We are a nation of diversity and we all come from very different backgrounds, yet the entire population of the country is somehow bonded together. The feeling of togetherness is what the country stands for and this is all because of how the population of the country has learnt to grow. 

Managing the population of a country is also a big task. For the leaders of any nation, the thing that worries them the most is the health, wellbeing and safety of the population of a country. There are several factors and things that contribute to ensuring the health, safety and wellbeing of a country’s population. The kind of food that they eat, the kind of lifestyle that they live and even the kind of money that they earn. The concept of population and its safety is a very complex one. To make things simpler, several theories by experts were devised to make some decisions for the population of any country. One such example is the Malthusian Theory that is going to be talked about in this article.

We are going to dive deep into this concept through this article. This article has been carefully constructed and has been written with the intent to make the readers understand all the details that are involved in the process of making decisions for a population. The story of the Malthusian Theory is a very interesting one and that is why we suggest that students go through the entire article carefully and research some more about the concept on their own as well. 

The Malthusian Theory

Amongst the well-known theories of population, the Malthusian theory is one of the oldest. Thomas Robert Malthus, an economist explained this theory in his 1798 essay on the ‘Principle of population’. He then modified some parts in the essay next edition in 1803. 

 

To Quote His Own Words:

“By nature, human food increases in a slow arithmetical ratio; man himself increases in a quick geometrical ratio unless want and vice stop him. The increase in numbers is necessarily limited by the means of subsistence Population invariably increases when the means of subsistence increase, unless prevented by powerful and obvious checks.”  

      

This can be simplified as the following; the human population grows in an exponential format, it increases according to birth rate and concerning that the food supply increases at a slower rate. If the population keeps on increasing there will be a limit and shortage of food. The shortage of food also indicates the increasing population. This increasing growth if not checked can put a strain on the economy, the environment, government, and the overall infrastructure of various social institutions. 

 

A simple example can be that in a family if every member of the family reproduces, the family tree will continue to grow, but food production grows at an arithmetic rate which means that it only increases at certain points of time. If left unchecked, as per the theory, a population would outgrow its resources.

 

Critical Elements of The Malthusian Theory of Population Growth

There are four major or critical elements of Malthusian theory. These are explained below.

 

An example can be the following sequence: 5,10, 50, 250, 1250….the common ratio is 5

 

Coming to food resources, the production increases in an arithmetic progression which is a sequence of numbers in such a manner that the difference between back-to-back terms is a constant.

 

Example: 3, 7, 11,15,19… the common difference is 4.

 

From this, he derived that a population grows faster than the supply of food and exponential population growth will lead to a shortage of food.

• Preventive Checks: The principle behind this check is to bring down the birth rate to control the population. Preventative checks arise from fore-sight which enables anyone to see distant consequences if he has a large family. If the family has many children the standard of living is bound to below. The only way anyone can support a large family would be through strenuous labour than what he does in the present state. If he is not able to support the family then the family members may be exposed to poverty. So, man must self-restraint himself from marriage or starting a family unless he thinks that he can support a family. 

• Positive Checks: The basis of this check is that population growth is shortened by various factors such as warfare, disease, famine, etc. As a result of these factors, the population would be reduced to a level that can be sustained by the available quantity of food supply. Malthus stated that positive checks would result in a Malthusian catastrophe which forces a return of a population to basic survival.

 

Why Was The Malthusian Theory of Population Criticised?

Since its inception, the Malthusian theory attracted criticism because of its principles. Below is a summary of some of the grounds on which the theory has been criticised.

 

Malthus made gloomy forecasts about the economic conditions for future generations based on population growth. However, contrary to the theory, the human population has not increased rapidly and the production of food has increased due to the technological advancement in the agricultural and other food sectors. The living standards of the human population have improved.

• One of the major supporting factors behind Malthus’s theory was that food production would not be able to keep pace with population growth due to the operation of diminishing returns in agriculture. However, recent advancements in technology along with large capital investments in the agricultural sector have been able to postpone the stage of diminishing returns. Usage of high-quality seeds, fertilisers, pesticides, and top-grade machinery have assisted agricultural growth. One of the best examples regarding the aspect is the Green Revolution in India. Introducing improved methods in farming and new inventions have increased food production to such an extent that it can sustain a growing population.

• Malthus stated that fertile lands used for food production were available in limited quantities, which is why food production can never rise faster than population. However, he never took account of different types of food production whilst considering the size of the population.

• England did face a shortage of agricultural land and if the country had to feed its population through farming then it would have suffered from famines. However, that was not the case as the industrial revolution made use of the
  country’s various natural resources such as coal and iron and made goods which were exported to other countries in exchange for food. Malthus made the mistake of only considering agriculture and food production when it came to sustaining a growing population.

 

The Importance of The Malthusian Theory

There are some elements of the Malthusian theory which have some weightage. Humans have a strong desire to reproduce. This is to maintain the family lineage and legacy. So the population is bound to grow rapidly if birth control measures are not taken.

 

Malthus’s assumptions regarding positive checks are true to a certain extent. History has shown that whenever there is an increase in population for any country, thousands have died due to natural calamities.

 

After studying these points, one can say that the theory is valid to a certain extent. Some of the leading economists of modern times have observed that Thomas Malthus in this theory regarding population growth has stated the partial truth and no one can deny that.

 

Malthusian Theory Summary

Based on the principles of the Malthusian theory it can be summarised into the following points:

• The growth of the human population is much faster than the rate of growth for the means of subsistence such as food, clothing, and other agro-products.

• As the production rate of agro products is slower it is surpassed by population growth which results in the onset of poverty

• Control of the growth of the population is important to sustain the population.

• Positive checks restore the balance between the increased growth rate of population and food supply.

 

Conclusion 

As mentioned from the very beginning of the article, the health and well-being of a country’s population are a big deal and that is why several theories like this one were made. We hope that this article was helpful for you to understand and get a good idea of what the Malthusian Theory of Population was. The article covers some really interesting facts that we encourage our students to research on their own and increase the arsenal of their knowledge. Thank you for reading this article from . We are grateful for you and we wish you very good luck for the next exam that you are preparing for! 

The estimation of enormous distances is simple. We realize very well how to magnify. We use kilometers for terrestrial applications, light years for a long time for heavenly applications, and 1 parsec (3.26 light-years) for galactic applications. On the opposite end of the scale, we have a little measure. We can get millimeters and our naked eyes can see up to 0.1 mm however after that it is extremely difficult to imagine. 

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An electron magnifying lens is a microscope that enlightens the sample with light emission electrons. This permits the electron microscope to concentrate pointedly on a little item, for example, an atom. This electron can be made to have a short frequency, right around multiple times shorter than the visible light, along these lines giving the electron microscope a better resolution than an optical magnifying instrument. A transmission electron magnifying instrument can accomplish superior to 50 Picometer (10-12) resolution and you ought to remember that atoms range from 30 – 300 Pico meters.

Prior to the innovative progressions, however, we just had a rough estimate of the size of the atom. Let’s examine a few of the methods or techniques now. 

Oleic Acid: Thin Film Method

The particles/molecules of oleic acid and other such vegetable oils have a place with a classification called lipids. These are normally called ‘fat particles/molecules ‘. Their structure is hydrophobic, which implies that they are inadequately dissolvable in water. Molecules that can be dissolved in water are called hydrophilic. The word originates from the Greek term signifying ‘water-loving’. Fatty acid molecules, for example, oleic acid are fascinating because they have parts that are hydrophilic and hydrophobic parts.  

In the image of oleic acid, note that the oleic acid particle/molecule is remaining on the – OH end of the molecule. This was done deliberately in light of the fact that when oleic acid particles/molecules experience water they stand upon it with this end down. Oleic acid buoys on water because of lower thickness. A noteworthy bit of the molecule is hydrophobic. Just the –OH end is hydrophilic. 

Since it is so larger than the hydrophilic end, the whole molecule isn’t solvent in water. At the point when putting on water, oleic acid molecules will stand up and bolster each other on end in light of attractive forces between the hydrophobic parts of the molecules. If oleic acid is dropped onto water, we make the supposition that it spreads out to a thickness of just a single particle/molecule.

There is a need to dissolve 1 cm3 of oleic acid in 400 cm3 of liquor to get a centralization of 1 part by 400. After that take a big water container and to the surface, we include a uniform layer of lycopodium powder. To this, we include one drop of oleic acid. The drop rapidly extends into a thin, huge circular film of molecular thickness. This is the oleic acid molecules remaining on their hydrophilic ends. 

How To Calculate The Thickness Size of A Molecule?

We can quantify the distance across this circle utilizing which we can compute the area ‘A’. 

Let us assume that the volume of one drop is ‘v’

Then,

The volume of n drops is ‘nv’ for the solution.

 

So, 

The volume of oleic acid in ‘n’ drops of solution = (nv/400) cc 

If the area is A cm2 and thickness is ‘t’

Thickness can be calculated as: (with the assumption that the thickness is equivalent to one layer of molecules) 

[A^ast t=frac{nv }{400}]

This implies the thickness is:

Thickness=Volume/Area 

[t=frac{nv }{A^ast 400}]

In light of the assumption that the layer is one molecule thick, we acquire the estimation of the size of the oleic acid molecule. The value of the thickness comes out to be in the order for 10-9 m. Taking into account how basic this exhibition is, this technique has generally excellent precision.

Microwaves attract all the attention when it comes to making our lives simpler in terms of cooking food. This article covers the properties of the microwave and also its production. We will also be discussing the difference between radio waves and microwaves. If you encounter any doubts while reading this article then the frequently asked questions at the end may help you out with those.

Microwaves are electromagnetic radiation as are ultraviolet radiation X rays, gamma rays, and radio waves. Microwaves have a range of applications including radar communications and best known by most people, cooking. 

During primitive days, ancestors used wood, coal to cook their food. With the evolution of human beings, the cooking style also changed, and people started using LPG. Today, in modern times, we have significantly evolved with technology and use microwave radiation for cooking food quickly at our convenience.

So, let’s understand microwave radiation. Microwave radiations are electromagnetic radiations with a frequency range of 300 Mhz – 300 GHz. The wavelength of the microwave spectrum range is between 1 mm to 30 cm. These radiations are often called a microwave.  In the electromagnetic spectrum, the microwave is present between infrared and radio waves. With this understanding, let us learn the characteristics of microwaves.

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Properties of Microwaves

• Microwaves are reflected by metal surfaces. 

• They pass through glass and plastics.

• They can pass through the atmosphere. Thus, microwaves are used phenomenally in information transmission back and forth to the satellite. It is why satellite dishes are composed of metal content as metal reflects the microwave radiation.

• Water absorbs a particular frequency of microwaves. This feature of microwaves is utilized in cooking food. Microwaves are absorbed by the water content present in food, which in turn heat the food. By heating, the atoms and molecules of water in food start vibrating. As a result, the temperature of the food increases, and the food is cooked.

• Microwave transmission is affected by wave effects like reflection, refraction, diffraction, and interference.

• The time for which the material is exposed to the radiation intensity determines the amount of heating.

• Microwaves are reflected by the conducting surfaces and travel in a straight line.

• They radiate electromagnetic energy with a shorter wavelength.

• The most suitable for the radar systems that are used in aircraft navigation due to their shorter wavelength.

How are Microwaves Produced?

Microwaves are generated by vacuum tubes devices. These devices work on the ballistic movement of electrons operated by either magnetic or electric fields. There are a few examples of microwave emitters like cavity magnetron, the klystron, the traveling-wave tube(TWT), and many more. These instruments work based on clumps of electrons flying ballistically through them, instead of using a constant flow of electrons. Lower power microwaves can be produced by some solid-state devices such as the FET (field effect transistor), the tunnel diode, the Gunn diode, and the IMPATT diode.

Production of Microwaves

1. Microwaves are produced by special vacuum tubes like the klystron, magnetron, and Gunn diode.

2. The frequency of microwaves is selected to match the resonant frequency of motor wall equals so that the energy is transferred efficiently to the kinetic energy of the molecules.

(a) Associated with the greenhouse effect.

(b) and also in remote switches of electrical appliances.

Radio Waves v/s Microwaves

Fun Facts

Did you ever think that we use a plastic or glass container in a microwave oven and not metal containers to heat or cook food? It is because the metal is microwave reflectors. On the other hand, glass and plastic allow the microwave to pass through them.

It is very commonly believed that a microwave is not suitable for health as it emits radiation. Nevertheless, there is a point to note that microwaves use the electromagnetic spectrum at low frequencies. Hence microwave radiations have low energy. Due to this insufficient energy, microwave radiations are not capable of changing the food substance chemically via ionization.

Microwaves traversed through the atmosphere will be absorbed by water. This process is utilized by the weather department to monitor rain.  If weak signals are reaching the detector, microwaves have passed through more rain. It helps in the analysis of rainfall. The weaker the signal reaching th
e detector, the more rain has passed through the microwave radiation

Conclusion

This is all about microwaves, their properties, production, and uses. Focus on its features and find out the difference between microwaves and other radiation waves. Understand how it is being used in different aspects of our modern lives.