Category: Physics Notes PPT

Generally, discovery is recognizing or finding something that already exists for the first time that nobody had even heard about or found before, e.g. how Christopher Columbus discovered America. On the other hand, an invention is creating or forming something totally new with one’s own ideas, knowledge, interest, and development and hence inventions are considered unique always.

Definition

Discovery: A discovery is a process of identifying and recognizing something that already exists, for the first time, that nobody has ever found before.

E.g., how Christopher Columbus discovered America.

Invention: An invention is, on the other hand, a process of creating something totally new and unique with one’s own ideas and development.

Discovery and invention have come a long way, and students have often been confused between the two. However, you should note that there is a significant difference between invention and discovery. To understand the difference, it is vital to have a prior understanding of the terms individually.

Although both these terms, discovery and invention, indicate bringing of something new in the limelight or forefront, they differ at their grassroots. You have to understand the relevant points of distinction in order to delve deeper into their individual concepts. 

Besides, make sure you are aware of the proper example for both of these terms. It will help you in clearing your doubts properly. Examples have always served a vital purpose when it comes to understanding a specific concept.

How Do You Differentiate Between Discovery and Invention?

To understand what is the difference between invention and discovery, examples are the simplest methods. However, it is important to understand the terms from their grassroots so that you can develop a better understanding of the advanced concepts.

 

Here is a Table for Showcasing the Difference Between Discovery and Invention for Your Convenience –

 

Here, the above table shows the difference between invention and discovery. Students need to go through these points thoroughly for a better understanding.

 

For more information on invention and discovery difference, you can look into our online programs. These are drafted by eminent faculties and you can develop your understanding to a new height.

 

So, get your study lessons and boost your preparation right away. You may also download our app for advanced learning.

Conclusion

Topics like invention-discovery differences, where they are almost similar and are often confused, should be dealt with examples. It will not only help in clearing the doubts but also help students in building the foundation for each topic.

LCD

LCD stands for liquid crystal display. Liquid crystal is a kind of material that is neither liquid nor a solid, it comes in between these two states of matter. It has properties similar to that of the crystallised solid. The arrangement of molecules is in a fixed pattern however they are not fixed in shape or form.

LED

LED stands for light-emitting diode and it is a semiconductor light source that emits light when current flows through it.

It is a type of flat-panel display that uses an array of light-emitting diodes as pixels for displaying images.

It comprises two sheets of polarising material with a liquid crystal solution between them.

Full-Form of LCD and LED

LCD

This technology is used in laptops, digital clocks, watches,  digital cameras, watches, etc.

There are three types of LCD TVs

1. Flat-screen LCDs

2. Front projection LCDs

3. Rear projection LCDs

LED

They are usually found in smartphones, televisions, computer monitors and instrument panels and use a liquid crystal display panel to control where the light is displayed on your screen.

There are 3 types of LEDs based on their backlighting methods:

1. Edge-LEDs

2. Dynamic RGB LEDs

3. Full-array LEDs

Working Principle of LCD Monitor

To display anything on the screen, three major components are necessary, they are

1. Light: A source through which you see the objects.

2. Colour: To view the objects in different colours otherwise everything on the screen will appear white.

3. A way to control the light and colour on the screen.

These three components are found in LCD. 

LCD  uses liquid crystals in its main form of functioning to produce a visible image.

Principle

It is a type of flat-panel display technology that uses diodes, small cells and ionised gases for the production of images.

LCD works on the principle of blocking light.

It also works on the modulating property of light where light modulation is the technique of sending and receiving the signal through the light. 

Working

A light is non-polarized by nature when passed via a plane. It scatters in different directions and phases as you can see in the image below:

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On placing the polarization filter (either horizontal or vertical) and passing the same light through this filter. 

The filter would polarise the light in one phase and produce a clean polarised light which you can see on your computer and TV screens.

The image below shows the polarised light:

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In LCD displays, light emitted from the backlight passes via a vertical polarisation filter after going through the liquid crystal element, this liquid crystal element twists this light wave. The vertically polarised light then turns to a horizontally polarised light. This horizontally polarised light passes via the horizontal polarisation filter allowing the passage of light. Hence the light is visible to us. The voltage we apply to the LCD is applied in such a way that the crystal mechanism of the light is removed and the light acquires a straight pattern. Due to this, the vertically polarised light will come out vertically only, however, the horizontally polarised light will be blocked and we won’t see any light in this case. This is how LCD works on the principle of blocking light.

The image below shows the working of LCD:

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Difference between LCD and LED

Applications of LCD and LED

Here are some applications of LCD:

• Portable electronic games 

• As viewfinders for digital cameras and camcorders

• In video projection systems

• Electronic billboards

• Computer monitors

• Flat-panel televisions

Here are some applications of LED:

• Digital watches

• Digital computers 

• Cell phones

• Bulbs and tubes

• Automotive heat lamps

• Camera flashes 

• Calculators

• Aviation lighting

• Microprocessors 

• Burglar alarms systems

• Traffic signals

• Multiplexers

We know that sound is produced from everything. These days, our activities in fact entire human living is based on sound. We begin our day with an alarm clock followed by many variants of sounds such as music, noise, vehicles, etc. Basically sound is the most essential part of our lives. Every living thing such as the roaring of a lion, crying baby, ultimately when we pour water into a glass we witness the production of sound. Now the question that arose is what is sound? 

 

A sound is a form of energy. The study of sound starts with the properties of sound waves and the types of sound waves. Basically sound is a form of wave or vibration. Human ears can sense the sound waves ranging from 20Hz to 20KHz, known as audible sound range. There are many variants of sounds such as pleasant sound, unpleasant sound, music, noise, soft, loud, etc. In this article, we will study the difference between sound noise music, what is meant by sound, what is the meaning of sound, types of sounds in physics, what is noise, etc.

 

Types of Sound

Before starting with types of sound, let us understand what is sound in physics? Sound waves are longitudinal, mechanical waves. Sound is caused by the back and forth vibration of the particles of the medium through which the sound wave is propagating. The vibrations of the object allow particles in the surrounding medium in vibrational motion, causing the auditory receptors to detect them. This is known as the sound. 

 

Though all the bodies that vibrate in the air can indeed produce sound, we can not hear all of them. Our ears are sensitive to a certain frequency range, depending upon this fact there are only two types of sounds i.e., audible and inaudible sound. The audible sound ranges from 20Hz to 20KHz. The sound waves that are below 20 Hz are known as infrasonic sounds and the sound waves above 20KHz are known as ultrasonic sound. 

 

Audible sound is further classified as pleasant sound and unpleasant sounds. So the pleasant sounds are the group of sounds that makes us feel relaxed like good music such as playing the piano, singing songs etc. At the same time, there are a certain set of sounds that will be unbearable or cause irritation to the hearing body like loud noises such as barking dogs, drilling machines etc. We can say audible sound can be classified into music and noise. 

 

Properties of sound

Sound in itself consists of seven major properties that either make it audible or inaudible, noise or music to the human ears. Different species of animals hear distinct sounds that can be inaudible to humans because of the varying properties of sound. 

Let us take a look at the properties of sound:

1. Frequency: Sound consists of sound waves. These waves are like the waves of water, they go up and down and then up again making a whole cycle. Frequency, or pitch, is the time taken by the soundwaves to complete an entire cycle. It is measured in hertz where one hertz (Hz) is equal to one cycle per second. 

2. Amplitude: The intensity of the soundwave is called its amplitude. The higher the sound waves, the more the intensity and the greater the amplitude. In common man’s language, we call it the volume of the sound. If someone is shouting, it means the sound has high amplitude while whispering can be considered as having low amplitude. 

3. Timbre: Have you ever heard two different instruments that play the same note yet sound so different? It is because they have different tones or timbres. Some frequencies that are lower in pitch are called subtones, while the ones higher in pitch are called overtones. Both of them combined to form ‘harmonics’ and give the sound distinct timbre or tones. 

4. Envelope: Envelope is simply how a sound wave or sound behaves over a particular period. It is also called ADSR, which is short for attack, decay, sustain and release. These are four sub-properties of the envelope. The attack is how fast a sound reaches its highest volume, decay is when it drops before it sustains a constant volume and finally releases into the atmosphere, almost vanishing. 

5. Velocity: The velocity of the sound is the speed at which the soundwaves travel through different mediums. Since, soundwaves use the medium of air to travel, the velocity of the sound can depend on different factors including humidity, temperature and density. 

6. Wavelengths: The difference between consecutive crests of the sound wave is called wavelength. Audible sounds have longer wavelengths than inaudible sounds. 

7. Phase: Phase is described as the difference between amplitude crests and troughs of two sound waves. It is measured in time, degree or distance. Two sound waves that have the same and are perfectly aligned to each other are said to be ‘in phase’; that is their phase difference is zero. It is important to know about the phase of sound to prevent ‘hollow’ sounds. 

 

What is Noise and Types of Noise?

Now, what is noise? So, noise is a type of sound, it is really important to distinguish between what is noise and what is sound. Noise is a type of sound and it can be defined as a type of sound that can be unpleasant, unwanted, annoying or too loud for human ears. 

 

Human ears are highly sensitive and excellent at identifying what is noise. Generally, noise is an annoying tone of sound that causes mild to major discomfort or irritation. These sound vibrations pierce through the background noise that accompanies our lives.

 

When it comes to measuring the different types of noise, we want to replicate how the human ear identifies noise to get an accurate interpretation of its impact. Thus, generally, we use something called the A-weighted frequency, which is much more sensitive between the 500 Hz and 6 kHz range. There are four different types of sound, as listed below:

1. Continuous noise

2. Intermittent noise

3. Impulsive noise

4. Low-frequency noise

Let’s discuss the four types of noise one by one as follows:

1. Continuous Noise:

• As the name suggests it is a type of noise that is produced continuously. 

• The examples of continuous noise are all the machines that run continuously without any breaks such as while riding a car we hear the sound of functioning parts like the engine, in factories large machinery produces continuous noise.

2. Intermittent Noise:

• Intermittent noises are noises
  that are not produced continuously. Intermittent noises are produced continuously but with intermediate breaks.

• The best examples for the intermittent noises are drilling machines, which we might have seen during the destruction or construction of any building we use drilling machines that produce unbearable sound. Another example of intermittent noise is drilling machines used by a carpenter or the dentist. 

3. Impulsive noise:

• It is a type of noise characterized by a noise level of more than 40dB within a half-second with a duration of one second. 

• Impulsive sounds incorporate almost all unwanted, instantaneous sharp sounds.

• Examples of impulsive sounds are bomb explosions, the fringe of weapons, etc.

4. Low-Frequency Noise:

• Low-frequency noise is produced from the objects around us in everyday life. It is one of the difficult types of noise to reduce, and it makes a silent room still register sound levels around 30-40 decibels.

• In an office setting, this noise is produced from a heating or ventilation system. In our house, it will arise from the ticking on a grandfather clock. Generally, we don’t even identify these types of noise unless we direct our attention towards them.

 So, these are the different types of noise and what is the meaning of noise physics.

 

Let us have a look at the difference between sound and noise as listed below:

 

Difference Between Sound and Noise:

 

These are the important differences between sound and noise. Similarly, we can note the difference between the sound and music, music and noise, etc. Learning the difference between these will help us understand the terms in a better way.

 

What is Music?

Music, by its definition, is referred to as vocal and instrumental sounds occurring one after another to create a beautiful symphony of harmony and expression of emotion. A music sheet is the written or printed signs representing these vocal or instrumental sounds.

 

The process of putting sounds and tones in a rhythm, mostly combining them to produce a unified composition is known as making music. Music-making is as much science as it is an art.

 

To create melodious music, you would need a musical instrument or instruments, these instruments create sounds with string, wind, and brass using special kinds of sound waves – known as ‘standing waves.

 

A wave that looks like it isn’t moving is called a standing wave. It only changes amplitude but doesn’t travel through any medium. The standing waves are the result of two other things waves do, reflection and interference.

 

When a sound wave travels through a path, reaches its end and then travels back, reflections occur. That’s what happens when you send a pulse down a rope – it reaches the end, and then comes right back.

 

When we send a continuous wave down the rope, that’s when interference comes into play. The sound wave after reaching the endpoint of the rope is reflected; however, there are more peaks on the path. As the peaks pass each other, they interfere with one another, changing their sizes.

 

Usually, it results in the formation of crests and troughs that are of varying sizes and various distances apart. But at particular frequencies, the reflected waves interfere in such a way that you end up with a wave that seems to stay perfectly still, with only its amplitude changing. That’s a standing wave, and it can be produced by both, the strings and the air in pipes.

 

That is what makes music: standing waves with different frequencies correspond to different musical notes.

 

Did You Know:

• Noise pollution causes hearing loss that is hazardous to human beings. People who are subjected to loud sounds regularly suffer hearing loss. The technical term used for this is Noise-Induced Hearing Loss (NIHL). Dangerous Decibels (an agency) researched the subject and discovered that out of the four million people in the United States who suffer from hearing loss, about 25% of those cases have NIHL.

• About 30 million people in the United States are subjected to hazardous sound levels at their workplace every day, according to a study from 2005.

• In 2015, the Centers for Disease Control and Prevention (CDC), found that mining was the industry with the loudest work environment, followed by manufacturing and construction. About one in eight of the workers in these and similar industries had hearing loss caused by their work environment.

Many people think that both cyclones and hurricanes are the same. Well, they do cause harm, but their formation and mechanism are different. This article will let you know the difference between hurricanes and cyclones in brief.

Both of the terms are very important to learn. Both are different from one another. Cyclone is a stormy atmospheric condition that promotes destruction as of its potential. Due to the instability in atmospheric conditions, the generation of the cyclone is possible.

The cyclone has different names based on different regions and severity. Hurricanes are one of the types that come under the category list of cyclones.

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What is the Difference Between a Hurricane and a Cyclone?

Both the cyclone and hurricane are based on simple facts and weather changes. These are the type of tropical cyclones that can cause chaos as they possess higher wind speed and promote floods with higher rain.

They are formed in the deep place of the ocean Water. The conditions that help the Cyclone to grow into its full form are available in the ocean.  

Do You Know What They are?

Heat and moisture: These two factors’ involvement makes the Cyclone big enough to work as havoc. Hurricanes are common in tropical areas of the earth. Due to random weather changes, ocean heat and vapour promote the birth of hurricanes. The places where the atmospheric pressure is the lowest, that’s the eye of a hurricane. Hurricanes are part of cyclones. Both are different in their terms. The tabular format will show you the diff between a hurricane and a cyclone:

Factors that Affect Cyclone and Hurricane

As both cyclones and hurricanes (part of the cyclones) are water-based natural tragedies, geologists and physicists need to understand water properties. This becomes the most important when you try to find out why it expands to this much. Also, they try to comprehend how cyclones and hurricanes work.

Are you looking for the factors that differentiate a cyclone from a hurricane? The answer is very simple. The lone difference between hurricanes and cyclones is the geographical location. Location and atmospheric conditions are the factors for these two calamities. 

The presence of a tropical system is found in the following oceans: 

• In the Atlantic and Northeast Pacific oceans, the natural disaster caused by the atmospheric change is called a hurricane. 

• In the north Indian Ocean, the name of the natural disaster caused by the atmospheric change is called a cyclone.

Disasters

Life is extremely unpredictable. Human life is constantly subjected to the perils of nature for human miscalculations. when death and destruction occur on a large scale during natural or human activities is called a disaster.  A disaster is an event that occurs suddenly and causes the loss of human life and property. It disturbs the environment and leads to economic loss.  awareness and preparedness are important to cope with disaster and disaster effects of the functioning of the society. Some disasters like floods and earthquakes have immediate effects on the surroundings. while others like drought have less impact initially but the effects can be severe over time. Disasters can be categorized as natural and manmade disasters.

Types of disasters

• Natural disasters

• Man-Made Disasters.

Natural disasters are caused by nature which is powerful and uncontrollable and occur suddenly. These events occur due to Earth’s natural processes. such disasters can cause damage to life and property. It is very difficult to recover the losses and rebuild communities after natural disasters. Floods, earthquakes, drought cyclones, landslides, volcanic eruptions, sinkholes and tsunamis are some of the examples of natural disasters.

Cyclones are caused by atmospheric disturbances around low-pressure areas. winds with a great speed move towards the intense low-pressure area as known as the eye of the cyclone. The edge of the cyclonic eye is called the wall of cyst, the ion of devastating winds. strong winds having great speed circulate the centre causing violent storms. They occur in the warm oceans in tropical and temperate regions of the world. cyclonic winds blow in the anticlockwise direction in the Northern hemisphere and a clockwise direction in the southern hemisphere. These winds cause great Havoc and large-scale destruction. cyclones are Storms known by different names in different parts of the world

Typhoons in the Northwest Pacific Ocean, hurricanes in the Atlantic ocean, and  North Eastern Pacific Ocean cyclones in the Indian Ocean.

LEDs are also known as light emitting diodes, it’s a semiconductor light emitting source that emits light when current is flown through it. Semiconductor electrons recombine with the electron holes releasing energy in the form of photons. Corresponding to the energy of photons the colour of light is determined, and also by the energy required by photons to cross the semiconductors band gap.  By using multiple semiconductors, white light is obtained or by a layer of light emitting phosphor on the semiconductor device.

The particle electronics components appeared in 1962. The earliest LED emitted low intensity infrared light in remote controlled circuits such as those used with a wide variety of consumer electronics.

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History of LED

A phenomenon known as electroluminescence was discovered in 1907, by the british experementor named H.J Round of marconi labs by using a crystal of silicon carbide and cat’s-whisker detector.

Oleg Losev, a Russian inventor, reported creation of the first LED in 1927. His research was distributed in Soviet, Germany, British scientific journals but no practical use was made of these discoveries for several decades.

Georges Destriau, in 1936 observed that electroluminescence could be produced with zinc sulphide power is suspended in an illustrator and an alternating electrical field is applied to it. In his distrial publication he often referred to luminescence as losev-lights.

He worked in the lab of madame Marie Curie, also an earlier pioneer in the field of luminance with research of radium.

Hungarian Zoltan Bay along with Gyorgy Szigeti, in Hungary pre attempted LED lightings in the year 1939 by pertaining a lightning device with an option on boron carbide, that emitted yellowish white, white or greenish white light depending on the impurities present.

Carl Accardo, Edward Jamgochain and Kurt Lehovec, explained these first LEDs in 1951 using an apparatus employing SiC crystals with a current source of a battery or a plus generator.

Types of LED

LEDs are made up of different packages and are used for different purposes.

These are mostly single die LEDs and they are available in various shapes and sizes from 2mm to 8mm through holes and the surface mount package. And the current rating ranges lie between 1mA to above 20mA. The multiple LED dies get attached to a flexible backing tape from an LED strip light. 

 These are the LEDs developed by the seoul semiconductor.  It can be operated             on AC power without a DC convertor. For each light cycle the LEDs part emits light which is dark. And this is reversed during the next half cycle. 

These high outputs or high power LEDs can be driven at currents from 100 of mA to more than an ampere. Some can emmite over thousands of lumen.

Overheating is proved to be destructive for the LEDs so the HP-LED can often replace an bulbe in a flashlight. It can be set in an array to form a powerful LED lamp.

Advantages and Disadvantages of LED

LEDs are used in many places here are some of the advantages of an LED:

• More lumens are emitted by LED per watt as compared to incandescent light bulbs. The LED lightning efficiency fixture is not affected by the size or shape, unlike fluorescent light bulbs or tubes.

• Colour LEDs can emit light of different colours without using any colour filter as the traditional lightning method needs. It can lower efficient costs, this is more efficient.

• Their size is adjustable from big to big and small to small. And are easily attached to the printed circuit board.

• LED lights up quickly, a red indicator light achieves full brightness light under a microsecond. At times the LED gives a faster response.

Disadvantages:

• The LEDs performance largely depends on the ambient temperature of the thermal management properties or the operating environment also.

• LEDs must be supplied with a voltage which is above their threshold voltage, and current below their rating.

• Area light source: the single LEDs do not approximate a point source of light which is giving a spherical light distribution.

Uses of LED

Uses of LEDs fall majorly under four categories that are:

In the visual signals where the light goes more or less directly from the source inside the human eyes, it does so to convey a message or meaning.

In illumination: where light is reflected from the objects to give visual responses. Interacting and measuring with the processes involving no human vision.

It’s also used in the narrow light sensor where LEDs operate in a reverse biased mode. And they respond to the incident light also instead of emitting light.

Due to their small size they can easily be fitted in anywhere and can be used time and again they are also available in many different shapes and sizes according to the users requirements.

Distances to the stars were first determined through an approach known as trigonometric parallax, a method still implemented for the nearby stars. To measure the distance to nearby stars, astronomers observe an object’s stellar parallax, which is the apparent shift of an object relative to some distant background. Parallax is the only direct method for measuring stellar distances.

Taking the radius of the Earth’s orbit into consideration as a baseline, the distance of the star can be measured from the parallactic angle, p. However, if p = 1″ is one second of arc, then the distance of the star is 206,265 times the distance from Earth to the Sun in light-years.

The nearest star to Earth is Proxima Centauri, which is at the distance that equals 4.24 light-years. Proxima Centauri is a part of Alpha Centauri. The Alpha Centauri distance to the Sun is 4.37 light-years.

Thus, trigonometric parallaxes are functional for only the nearest stars to Earth, which lie within a few thousand light-years. For more distant stars, indirect methods are implemented to observe and measure; most of them depend on comparing the star’s intrinsic brightness with its apparent brightness.

What are the Earth’s Closest Stars?

There are only three stars, Alpha Centauri, Procyon, and Sirius, among the nearest 20 and amid the brightest 20 stars. Most of the Earth’s stars remain relatively nearby and are dimmer than the Sun and also remain invisible if viewed without the telescope’s aid. However, the Earth’s closest star is Proxima Centauri, about 93 million miles away. The most luminous stars close to Earth can be observed at great distances, while the faint ones can be seen if they are relatively close to the Earth.

The brightest and nearest stars fall roughly into three categories: (1) Giant and Supergiant stars that possess sizes of tens or even hundreds of solar radii and extremely low average densities. (2) Dwarf stars hold sizes ranging from 0.1 to 5 solar radii, and their masses range from 0.1 to about ten solar masses. (3) White dwarf stars have masses comparable to that of the Sun but have their average densities hundreds of thousands of times greater than that of the water.

What is an Astronomical Unit?

An Astronomical Unit (AU) represents the mean distance between the Earth and Sun. An AU (the distance from Earth to Sun in meters) is approximately 93 million miles or 149.8million km. It’s about eight light minutes. However, the Earth’s orbit around the Sun isn’t a perfect circle. Therefore, the Sun distance to Earth changes throughout the year. The average distance from Earth to Sun in light years, in AU, is one light-year is equal to 63,240 AU. Thus, it can be concluded that one astronomical unit is the approximate mean distance of Earth and Sun., where the distance from Earth to Sun in meters is about 150 million km or 93 million miles, or eight light minutes.

The Distance of Planets from Sun

Our solar system comprises the Sun, eight planets, moons, several plutoids, an asteroid belt, meteors, comets, etc. Eight planets orbit around the Sun and the distance of the planets from the Sun are influenced by several factors. Planets near the Sun receive more energy and have a warm or hot temperature, while the planets that are further away from the Sun receive less energy, and their weather is generally more relaxed. 

The distance of the planets from the Sun increases from Mercury to Neptune or Pluto. The distance from Earth to Sun is called an Astronomical unit, or AU, to measure distances throughout the solar system. The current distance between Earth and Sun is 149.83 million km. 

Distance Between Moon and Sun

Since the Moon orbits the Earth and the Earth orbits the Sun, the average sun distance to Earth is the same as the distance between Moon and Sun. On average, the Moon and Sun’s distance is about 150 million kilometers (93 million miles). This distance of Earth and Sun is so considerable that it takes light eight minutes to reach the Earth and its satellite which means that if the Sun stopped shining, there would be a void of eight minutes. When the Moon is the farthest away, it’s 252,088 miles away from the Sun, which means 32 piles of Earth away. When it’s closest, the Moon is 225,623 miles out, between 28 and 29 Earths.