Category: Physics Notes PPT

Let the initial position of a particle be x0 and position at time t be x. Then its displacement relative to x0 is x – x0 and it depends in some manner on time t. We say that displacement varies with time or is a function of time t.

 We denote the function by ft. Thus x – x0 = ft ,

Here the expression for function depends upon type of motion. If the motion is with uniform velocity we have x – x 0 = Vt linear function Here we say that displacement x – x0 is proportional to t. Position x = x0 + Vt is said to be a linear function of t as power oft is 1. The graph of xt is a straight line. 

If the motion is along the x-axis with uniform acceleration, the displacement is given by x – x0 = ut + ½ 2  at 2. 

Here we have quadratic function oft as the highest power of is 2. The graph of xt is a parabola. If acceleration is not uniform we have an infinite number of ways in which acceleration can change. Of these, one special case is very important-arising from a periodic function of time.

Derivation of Displacement as a Function of Time

In order to understand displacement as a function of time, we will have to derive an expression for displacement also known as the Second equation of motion.

 Let us assume a body traveling with  an initial velocity of v1 at time t1, and is subjected to some constant accelerations thus making its final velocity of v2 at time t2, 

Keeping these things in assumption let’s derive the following.

We know that average velocity is equal to total displacement covered in a given time interval. Thus using this we can say that

V average = Total displacement / Total time  

Displacement = V average Δt

Where Δt  is the change in time and is equal to t2-t1

Since acceleration is constant thus average velocity is mean of initial and final velocity

Therefore ,displacement  = (V1+ V2/2) Δt , where V1 and V2 are initial and final velocity 

Now, since acceleration is constant, final velocity

 V2 = V1 +at 

d = ((V1+V1 + aΔt) /2 ) Δt

 Now we can if we rewrite the above as,

d = (2V₁+ aΔt) Δt /2

The above expression is second equation of motion and is one of the most fundamental expressions in kinematics and is finally reduced to 

d= V1 t+½ at2

Where V1 is the initial velocity and t is the change in time, all the quantities in this derivation like Velocity, displacement and acceleration are vector quantities. 

Thus, the above expression clearly proves that displacement depends upon the time .

Example of an Oscillating Pendulum

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When Bob reaches the highest point, the potential energy is maximum and the kinetic energy is minimum as the velocity is equal to zero but the total energy is conserved throughout the motion and only transformation from kinetic energy to potential energy or vice versa will take place. 

Thus we can easily deduce that the velocity is equal to zero, by looking at the slope of the displacement-time graph at specific times.

The Slope of the graph at A is positive stating that the velocity of the body is also positive, or in the forward, direction while Slope at B is equal to zero meaning that the velocity of the body is zero, while acceleration is still there that later imparts velocity in reverse direction.Thus slope at C is negative in the graph means that the velocity of the body is also negative, or in the reverse direction.

If we draw a displacement-time graph of this oscillating pendulum we will get something like this as shown below in the figure. Here the magnitude of velocity is always positive, it is the direction that decides if the velocity is positive or negative.

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The displacement of the bob of the pendulum is periodic in nature as it repeats itself after a certain amount of time. Also the displacement at any given time in the future can be predicted with the help of graph since we know the time and the time period of the pendulum. 

Thus we can say that displacement of the oscillating pendulum bob is a function of time.

We all love to play with a ball, so when we throw a ball, it deviates from its original path instead of making a projectile motion. So, the deviation of this ball is called the Magnus Effect.

The Magnus Effect is an observational phenomenon that is closely related to spinning objects traveling via air or a fluid.

When we see an airplane flying in the sky, a question comes to our mind: how do wings take a lift? Is there something that lifts the wings up? Yes, there’s a force that lifts the wings of a plane.

How Wings Take Lift?

The two examples we discussed above are Dynamic Lift and Magnus Effect applications, and now we will discuss these in detail.

Airfoil technologies have drastically changed the way we live. This technology drives gas turbines, flying wind turbines, and hydraulic machines. 

An airfoil is a shape that has revolutionized the world of Engineering Physics. An airfoil is a shape that produces a lift when fluid is forced over it. So, what is the source of this lift? 

                         

According to Bernoulli’s principle, the particles at the upper surface should travel more distance than those at the lower surface. 

Since the particles at both the surfaces need to reach the end-point simultaneously; therefore, the velocity of upper particles should also be greater than the lower one, as it has to cover a greater distance; this means that the pressure at the top is lesser and at the bottom is high. This pressure difference generates lift. 

The argument we discussed above is called the Equal-time argument. However, this was proved wrong, as the particles on the upper and the lower surface can’t reach simultaneously; also the path wasn’t streamlined.

We can see that the high pressure brings the curvature in the fluid flow, as we can see in Fig. So, the more is the curvature, the more is the lift. 

Now, we will apply Newton’s third law to understand How Wings Take Lift?

We can see that airfoil pushes the fluid downward, so according to Newton’s third law, the air also generates an equal and opposite reaction force on the airfoil, which results in the lift. 

                 

What is a Dynamic Lift?

We understood how wings take the lift. Now we will study the science behind it.                          

While seeing an airplane, we ask ourselves why the wings of a plane are at a certain angle; for that, let’s take a look at a new figure:

                      

The wing of a plane is at a slight angle, and this causes the air streamlines at the upper surface group together, as shown below:

                    

We can see that the area between the streamlines has reduced a bit. So, by Bernoulli’s Principle, the mathematical expression for the same will be:

                       A1V1 = A2V2……..(1)

This equation is called the continuity equation.

Here, 

A1 is the area between the streamlines at the upper surface

V1 = Flow velocity of the streamline at the upper surface

A2 = area between the streamlines at the lower surface

V2 = Flow velocity of the streamlines at the lower surface

What happens here is, as the space or gap between the streamlines reduces, the velocity increases. From expression (1), we can understand that the area is inversely proportional to the streamline’s velocity, i.e., high velocity, low pressure and low velocity, high pressure. 

Now, considering the direction of the wings and the air molecules. If the wings are traveling in the positive x-direction, and the air molecules are rushing past to the wings. 

So, if we take the reference frame of the wing, then we are going to have streamlines of air that will rush in the direction of air molecules along the x-axis. 

Since the direction of the wing is along the direction of motion, along the x-axis and also they are bent by some angle, that’s why the streamlines at the upper surface come close to each other and are separated at the bottom surface of the airfoil. 

So, from equation (1), we understood that the pressure difference creates an invisible force, which acts along the y-direction, and that force is nothing but the lift. This lift is known as the Dynamic Lift. 

Mathematically, we can express the Dynamic Lift as:

      F = ΔPA…..(2)

So, what is Dynamic Lift? It is a force that lifts our wing, and therefore, lets our plane continue flying in the air. 

Summary

We understood from the above explanation that area reduction between the streamlines increases the velocity, and from the continuity equation, when the area decreases, the volume increases; this, in turn, increases the flow velocity of the streamline at the upper surface. Since the velocity at the upper surface is higher, that’s why the pressure will be lower, while at the lower portion, it will be higher.

As the difference arises, there is a force that lifts the wings and helps the plane continue its flight.

Elasticity is defined as an attribute of rigid bodies to restore their original shape. Consider a spring hanging at one end through a rod at the top and the other end of it is left free. If I stretch this free end, the spring starts vibrating back and forth. It means the potential energy stored inside it transforms into kinetic energy; the spring is in solid form, so there is a tiny space between the successive atoms. Due to the force of attraction between them, they try to come back to their lattice points. This is how an interatomic force of attraction comes into play. So soon the stage comes when restoring force acting in the opposite direction to the applied force brings the spring into its natural state. Hence, the condition in which the body rolls back to its initial form. Such a condition is elasticity.

Explain Elastic Behaviour of Solids

Solid is one of the three states of matter composed of many molecules or atoms arranged in a particular form. Here, each molecule is acted upon by the forces because of neighbouring molecules.  The solids take such a shape that each molecule finds itself in a position of stable equilibrium. The rigid bodies when stretched with an external force restore their original shape after the removal of this force. It means they are in an elastic limit. So, until the elastic limit, the body resists the changes. Therefore, we can say that the body is perfectly elastic. Thus, the elastic behaviour of solids can be explained very well by observing the microscopic nature of the solids. 

Elastic Behavior of Solids

When a solid body is deformed, the atoms or molecules inside it are displaced from their fixed points or lattice points (equilibrium positions) causing a change in interatomic and intermolecular distances. When this force is removed, the interatomic force tries to bring back the body into its original position. Thus, the body comes to its original shape.

Mechanical Properties of Solids

The restoring mechanism can be visualized through a model of a spring ball system.  Here, the ball represents atoms and spring represents the interatomic force of attraction between the balls or atoms. 

Initially, these atoms are in their respective lattice points as shown in Fig.2. When they are displaced from their points, the interatomic force of attraction brings the system to its original shape.

Deformation: The phenomenon of change in the shape of a body under the effect of applied force.

Deforming Force: The external force that is responsible for deformation in the shape of the system is called the deforming force.

Restoring Force: The opposite force that works in the way the frictional force does in a moving body. This force acts in the opposite direction, and it is a property of a body to come back to its original position after an external force is removed.

Physical and Chemical Properties of Solids

• Solids are incompressible, which means that the constituent particles are placed close to each other, resulting in little space between the constituent particles.

• Solids have a fixed mass, volume, and form, resulting in a compact arrangement of component particles.

• Solids are inflexible. This is because there isn’t enough space between the constituent particles, which causes it to be hard or fixed.

• Molecules have a small intermolecular distance. As a result, the force between component particles (atoms, molecules, or ions) is extremely strong.

• Particles in the system can only fluctuate about their mean locations.

• The melting point of a solid is determined by the strength of the interactions between its constituents: stronger interactions result in a higher melting point.

Important Points on Elastic Behaviour of Solids

The attribute of a matter or a body under which a body regains its original configuration is called elasticity.  Let us understand this through an experiment:

On stretching a rubber band, we observe that there is a change in its shape and size. On releasing the band, the rubber regains its original length.

The force applied to the rubber band is the deforming force. Therefore, the force that restores the elongated body to its original shape, and size is called the restoring force.

What Causes this to Happen?

Depending on their atomic elasticity, solids are formed up of atoms (or molecules). They are surrounded by other atoms of the same type, which are kept in balance by interatomic forces. When a force is applied to the solid, these particles are displaced, causing it to distort. When the deforming force is eliminated, the atoms revert to their previous state of equilibrium due to interatomic interactions. Because no substance is fully elastic, elasticity is an idealization.

Applications of Elastic Behavior of Materials

Elastic materials are those materials that can be used in places where the long-term usage of such material is required. The applications of elastic materials are outlined below:

• Used in the construction of bridges, beams, columns, pillars: while constructing these materials, in-depth knowledge of the strength of the materials used in the construction is of prime importance.

• Construction of cranes: Cranes are used to lift the loads. Therefore, great care is taken into consideration that the extension of the rope does not exceed the elastic limit of the rope.

• In engineering, it is of utmost importance to know the elastic behaviour of materials being used.

• The bridges are designed in such a way that they don’t get deformed or break under a load of heavy traffic, or due to the force of strongly blowing wind, and its weight.

• Let’s consider a bar of length L and breadth d. Let Y be the young’s modulus of the material of the bar. When a load ‘W’ is attached at its middle point, the depression δ produced at its middle point is given by,

                         δ = Wl3/4Ybd3

Factors Affecting Elasticity

Effect of Stress: Even within the elastic limit, we know that when a solid is exposed to a high number of cycles of stresses, it loses its elastic characteristic. As a result, the material’s operating stress should be kept lower than the ultimate tensile strength and the safety factor.

Effects of Temperature: Temperature affects the elastic properties of materials. Elasticity rises with lower temperatures and decreases with higher temperatures.

Effect Nature of Crystals: The flexibility of the crystals also relies on whether they are single crystals or polycrystals. The elasticity of a single crystal is higher, whereas the
elasticity of a polycrystal is lower.

Effect of Annealing: Annealing is a procedure that involves heating a material to a very high temperature and then cooling it slowly. Typically, this technique is used to improve the material’s softness and ductility. However, annealing a material causes the production of big crystal grains, which lowers the material’s elastic properties.

Effect of Impurities: The presence of impurities causes variations in the materials’ elastic properties. The type of impurity introduced to it determines how much elasticity it gains or loses.

Differences Between Elasticity and Plasticity

• Elasticity is the quality of a solid material that allows it to restore its form once external stress is removed. Plasticity is the characteristic of a solid substance that allows it to keep its distorted shape even when the external load is removed.

• The amount of elastic deformation is minimal. The amount of plastic distortion is substantial.

• The amount of external force necessary to bend a solid elastically is relatively tiny. Plastic deformation needs a greater amount of force.

• Within this elastic zone, Hooke’s Law of Elasticity applies. If the material is plastically distorted, Hooke’s Law does not apply.

• Within this elastic area, most solid materials exhibit linear stress-strain behaviour. In the plastic zone, the stress-strain curve is non-linear.

• Although atoms of the material are displaced from their original lattice location during elastic deformation, they return to their original position once external stress is eliminated. As a result, atoms are momentarily displaced. Plastic deformation causes solid atoms to be permanently displaced from their original lattice location. They maintain their new location even when the external stress is removed.

• Elastic deformation takes place before plastic deformation. Only after it has been elastically deformed does it undergo plastic deformation.

The Similarity Between Elasticity and Plasticity

• Both are the qualities of Solid.

• Both forms of deformations can occur as a result of any sort of loading (normal, shear, or mixed).

• Depending on the application, both elastic and plastic deformations might be advantageous.

• Only when the material has been elastically deformed can plastic deformation begin. As a result, plastic deformation is impossible without elastic deformation.

An electric dipole is an arrangement of electric charges. Let’s say if one charge is negative then the other needs to be positive, provided that these two charges are of equal magnitude. Also, there should be a certain distance between these two charges.

Let’s suppose + q  and – q are the two charges separated by a distance ‘2a’, now joining the centre of these charges with a line, as shown below:

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The mid-point of this line is the centre of the dipole. The dipole has a certain length and also the moment.

Here, we are going to discuss electric dipole and dipole moment.

What is Electric Dipole and Electric Dipole Moment?

We understood that an electric dipole is an arrangement of equal and opposite charges. Since the two charges are separated by a distance ‘2a’, which is called the dipole length. The distance between the charge and the centre of the dipole is ‘a’.

So, what is an electric dipole moment?

The dipole moment is a vector quantity and is denoted by a symbol [overrightarrow{p}]. Its magnitude is equal to the magnitude of either of the two charges. Since we don’t specify the sign for the dipole moment, we multiply either of the two charges with the dipole length. It is given by:

                            [overrightarrow{p} = q overrightarrow{d}] ….(1)

Here, d  = 2a, so, we can rewrite the equation as:

                               [overrightarrow{p} = q(2a)] …..(2)

So, equation (2) is the magnitude of the dipole moment.

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So, what is the SI unit of the dipole moment?

We know that the unit of the charge is ‘C’ and that of distance is ‘m’. So, the unit of the dipole moment becomes:

Can we see the difference in equations (1) & (2)?

Yes, there is a big difference between the two, but how, let’s understand this:

See, in equation (1), we considered the distance ‘d’ as a vector quantity, however, in equation (2), both the quantities viz: charge and distance or dipole length are the scalar quantities. 

Now, when the product on the R.H.S of eq (2) are scalar, so, how can dipole moment be a vector quantity?  Yes, p can be a vector quantity only when we somehow convert the distance ‘2a’ as the displacement.

So, how can a distance be displaced, as these two quantities are different?

Now, let’s look at the following arrangement:

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When we take ‘2a’ displacement of the charge – q with respect to charge + q, .i.e., from L.H.S to R.H.S or of the charge + q with respect to charge – q (from R.H.S to L.H.S). Now, this  ‘2a’ becomes a vector quantity. Hence, equation (2) becomes:

                              [overrightarrow{p} = q(2 overrightarrow{a})]…..(3)

Or,                        [|overrightarrow{p}| = q times (2a)] …..(4)

So, what do you mean by electric dipole moment?

From eq (3), we define electric dipole moment as the product of charge and the displacement of + q charge with respect to – q charge.

Sometimes confusion arises in considering the direction of electric dipole moment. In Chemistry, we consider the displacement of + q charge with respect to charge – q, i.e., from right-to-left, while in Physics, we take the displacement of – q w.r.t. + q, i.e., from left-to-right.

There are two more units of the dipole moment, possessing a relationship between each. These are:

Also, 1 D = 10^-18 StatC . cm, which is approximately  = 3.33564 x 10^-30 C.m.

There’s something ideal included in the concept of dipole moment, let’s discuss it.

What is an Ideal Electric Dipole?

From eq (4): If the charge ‘q’ gets larger, the distance between the two charges becomes smaller and smaller,  to keep the product of these two quantities viz: ‘q’ and ‘2a’ as constant, i.e., [overrightarrow{p}| = q times (2a)] = constant, this is what we call it as an ideal dipole or point dipole.

Therefore, an ideal dipole is the smallest dipole having almost no size.

Significance of Electric Dipoles

We can find the application of electric dipoles in atoms and molecules, but how?

Consider one atom of Hydrogen and the other two of Oxygen in the water molecule. Now, what happens here is, a covalent bond forms between H and two O-atoms, and they come close to each other.

Since there is a difference in the electronegativity of H and O, there is a shift of charges; also, the centres of these atoms don’t coincide.

O is an electronegative element and a shared pair of electrons between H and O towards O. Therefore, the centre of the negative charge shifts towards O, and the positive one to the H-atom; also, a partial positive and the negative charge develops on H and O-atom, respectively. Now, the arrangement of H and O in the water molecule behaves like a dipole.

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Did it ever occur that items like glass, air, and wood could play a vital role in Electrical purposes?  It may come to you as a big surprise, but glass, plastic, paper, cardboard, wood, and even dry air are common Electrical Insulator materials.  Let us begin with the Electrical Insulator definition before discussing the properties of Insulators and the uses of Insulators.

What is an Electrical Insulator?

Technically, you need to understand the Electrical Conductor’s concept to master the topic of the Electrical Insulator, and the application of Insulator. The Electrical Conductor’s materials enable the flow of the Electrical current or charges in a single or multiple directions.  In other words, the Conductors of Electrical materials can be metals, like copper and non-metallic materials, such as graphite as they have free electrons.  For example, if you want to charge your mobile, you plug it in the socket.  The electrons present in the Electrical Conductor allow your phone to be fully charged. 

On the contrary, Electrical Insulator materials do not allow free flow of Electric currents or charges.  The Electrical Insulator materials give very little freedom for the electrons to drift from atom to atom.  Thus, Electrical Insulators are a poor Conductor of Electricity.  You can get a better understanding with the help of an Electrical Conductor example.  You must have observed that the outer covering of your phone charger plug is made from plastic so that the Electric charges do not pass on to human skin.  The following is a list of Electrical Insulator examples.

• Styrofoam

• Plastic

• Wax

• Rubber

• Dry air

• Glass

• Ceramics

• Rubber

• Teflon

• Mica

• Quartz

• Porcelain

• Asphalt

Uses of Insulators

You must be wondering why are Electrical Insulators important for us when Electric charges cannot be passed through it?  Generally, Electrical Insulators are highly useful at home, offices, streets, etc.  They are used in Electrical appliances and equipment.  Unfortunately, human skin is one of the best Conductors of Electric charges.   Furthermore, the presence of Electrical Insulator materials prevents and protects Electrical devices from generating high voltage.  There are innumerable uses of Insulators.  They are listed below.

• It prevents the passing of high-voltage in an Electric circuit.

• It helps in reducing the cost of energy.

• It helps in saving the environment by controlling the emission of pollutants.

• It improves process performances.

• It protects from Electric shock or electrocution.

• It allows the soundproofing of appliances.

Application of Insulator

Since the Electrical Insulator materials bind the electrons tightly, it prevents the electrons from floating from atom to atom.  Thus, they prevent the conduction of Electric charges.  Given the benefits of there are multifold applications of the Electrical Insulator.  They are applied to-

Types of Electrical Insulation in Overhead Lines

Electrical Insulators can withstand the charges from Electricity.  They are broadly classified into three types of Electrical insulation based on their operating voltage levels and applications.

Pin Type Electrical Insulator

A pin Insulator is best for supporting low voltage line Conductors. A single piece of pin Insulator is used in 11kV, and the double piece is applied to 25kV.  Above 44kV, three or four pieces of pin Insulators can be used.  An Electrical Insulator has a porcelain shell.  So even if the outer surface of an Electrical appliance gets wet, the inner surface is dry to keep it leakage resistant.

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Suspension Type Electrical Insulator

Suspension Electrical Insulators are best to handle high-voltage transmission lines.  This type of Electrical Insulator has porcelain discs inside arranged in a series through metal links such that they have a string-like appearance.  The arrangement of Insulators highly depends upon the weather condition, voltage, the size of the Insulator, etc.

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Strain Type Electrical Insulator

Another name for strain Insulator is tension Insulator.  They are best for high voltages when the Electrical line is subject to change in the direction of the line, and at higher-tension areas at sharp curves, river crossings, etc.  It is useful in minimizing the excessive tension in the line.   Strain Electrical Insulators have diElectric properties.  Additional strings can be added when the tension begins to aggravate.

Fun Facts

1. You would be surprised to know that the diamond necklace you wear on a special occasion is an excellent Electrical Insulator material.

2. A high-voltage area, which is dangerous, is enclosed in fiberglass or glass to prevent the conductivity of charges to pass.

3. Your Electrician uses a special screwdriver with a plastic coating to check the passage of Electrical charges without getting electrocuted.

Difference between Conductor and Insulator

Quick Summary

Here’s a quick summary of the topic of Electrical Insulators and their examples.

This was all about Electrical Insulators, properties and their types. For more such information, access free resources available on the website useful for the state board, CBSE, ICSE, and competitive examinations. All NCERT Solutions for all subjects are available on the website.

Infrared waves are also called heat or thermal waves. This phenomenon occurs because they have a particular heat-inducing property. These waves have a wavelength range between 710 mm to 1mm. Sometimes infrared rays themselves are categorized into near-infrared and far-infrared rays. Near-infrared rays are profoundly used in electronic applications like TV remote sensors and photography. Applications of Infrared rays in the real world can be somewhat similar to applications of visible light because their wavelength ranges are close by. Far infrared rays are generally more thermal. Anything which can generate heat gives out far-infrared Radiation. Even the human body (at approximately 37 deg-C) gives off infrared Radiation which is of around 800 nm wavelength. The infrared ray has many applications worldwide in different branches of science.

 

Hot objects and molecules produce infrared waves. The low-frequency or long-wavelength end of the visible spectrum (1mm to 700nm) is adjacent to this band. Heatwaves are a term used to describe infrared waves. This is due to the fact that infrared radiation is easily absorbed by water molecules found in most materials (many other molecules, for example, CO₂, NH₃, also absorb infrared waves). Their thermal motion increases as a result of absorption, i.e., they heat up and heat the environment. Physical therapy uses infrared lamps. The greenhouse effect uses infrared light to keep the earth warm. Earth satellites have infrared detectors, which are utilized for both military and agricultural purposes. Infrared is emitted by electronic devices (such as semiconductor light-emitting diodes) and is frequently used in the remote controls of domestic electronic systems such as televisions, video recorders, and wireless networks.

Characteristics of IR Rays

Below are a few characteristics of infrared Radiation.

1. Infrared Radiation characteristics are:

2. Infrared Radiation has its Origin from the Alteration in the movement of electrons.

3. Infrared Radiation has its Wavelength Range from   710 mm to 1mm

4. Infrared Radiation has its Frequency from:430 THz – 300 GHz

5. The infrared Radiation Wave type is, Transverse Wave

6. Infrared Radiation has its Speed of   3 ×10⁸ m/s

7. Infrared Radiation, Exhibits the property of refraction.

8. Thermal Properties of Infrared Radiation include: Exhibiting of heat-inducing properties.
   

Absorption and Reflection characteristics of Infrared Radiation is that they can be absorbed or reflected depending on the nature of the surface that it strikes.

IR Rays Use

Infrared Radiation is used extensively in applications like remote sensing, which is used in all types of weather applications. All bodies can give off some thermal energy, and by relying on this property, infrared rays have opened to us a wide variety of covert operations as well. Concerned with Infrared rays, they find their application in the field of astronomy too.

 

Infrared light can also be termed as warm light. The light which falls on our body when we sit near a campfire or even the light of the sun, these kinds of lights can also emit some thermal energy which can cause us to feel the heat. Infrared heaters also come under this category where they generally use infrared Radiation to generate thermal energy.

 

Infrared Radiation is often used in industrial, scientific, military, law enforcement, and medical applications. Night-vision devices are used extensively; active near-infrared illumination allows people or animals to be observed without detecting the observer. Infrared astronomy predominantly uses sensor-equipped telescopes which helps the detectors to penetrate dusty regions of space such as molecular clouds, detect objects such as planets, and it helps to view heavily red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used predominantly to detect heat loss in the insulated systems, which is used to observe changing blood flow in the skin, and to help to detect overheating of electrical apparatus.

 

Infrared Rays have extensive uses for military and civilian applications, including target acquisition, surveillance, night vision, homing, and tracking. Humans at average body temperature can radiate chiefly at wavelengths around ten μm (micrometres). Applications that are Non-military generally include thermal efficiency analysis, advanced environmental monitoring, new industrial facility inspections, prior detection of grow-ops, the technology of remote temperature sensing, different short-range wireless communication, spectroscopy, and weather forcasting.

Heating

As a heating source, infrared radiation can be used. Several studies have revealed some indication of benefit when utilising infrared saunas to address chronic health problems such high blood pressure, congestive heart failure, and rheumatoid arthritis. It is used to heat the occupants of infrared saunas, as well as to clear ice off aircraft wings (de-icing). Far infrared is also gaining favour as a natural health care and physiotherapy form of safe heat therapy. Because infrared heats opaque, absorbent things rather than the air surrounding them, it can be utilised to cook and heat food. Curing of coatings, shaping of plastics, annealing, plastic welding, and print drying are all examples of industrial production processes that use infrared energy.

Solved Examples

1. Which Rays are Used in TV Remote?

The primary technology which is used in remote home controls is infrared (IR) light. The signal that is present between a remote control handset and the device it controls includes the pulses of infrared light, which is invisible particular to the human eye but can be seen easily through a digital camera, video camera, or phone camera. The transmitter which is present in the remote control handset usually sends out a stream of pulses of infrared light when the user goes to press a button on the handset. A transmitter is usually known as a light-emitting diode (LED) which is generally built into the pointing end of the remote control handset. The infrared light pulses especially form a pattern unique to that button. The receiver in the device quickly recognizes the pattern and causes the device to respond repeatedly and accordingly.

Did You Know?

A hyperspectral image is a kind of “picture” which consists of a continuous spectrum through an extensive spectral range at each pixel. Hyperspectral imaging is extensively gaining importance in the branches of applied spectroscopy, particularly with NIR, SWIR, MWIR, and LWIR spectral regions. Typica and general applications include biological, mineralogical, defense, and industrial measurements. These applications are very much used to minimize our work, and continuously our technologies are enriched with the use of infrared rays.

Infrared Rays have a Healing Impact

• A beneficial effect on pain in the dorsal region and muscles, studs, bronchitis, and asthmatic disorders; help to normalize high blood pressure, enhance and stabilize blood circulation; a beneficial effect on pain in the dorsal area and muscles, studs, bronchitis, and asthmatic disorders;

• Aid in the treatment of colds, weariness, and exhaustion in the human body;

• Inflammation of the ears, nose, and throat;

• Reduce discomfort associated with arthritic and rheumatic disorders, as well as herniated discs;

• Improve kidney function

• In times of stress;

• In methods for cellulite removal and fat-digesting;
  

Infrared Rays and their Properties, as well as Infrared Light

Infrared radiation carries a large portion of the Sun’s energy to Earth. At sea level, sunlight at its zenith has irradiation of just over 1 kilowatt per square meter. Infrared radiation accounts for 527 watts, visible light for 445 watts, and UV radiation for 32 watts. The balance of infrared energy absorbed and emitted has a significant impact on the Earth’s climate. InfraredWavesBody Infrared light is employed in a variety of applications, including industrial, scientific, and medicinal. People or animals can be seen without being discovered using night-vision gadgets that use infrared illumination. Imaging at infrared wavelengths helps astronomers to see objects that are veiled by interstellar dust. Infrared imaging cameras are used to identify electrical devices overheating, monitor heat loss in insulated systems, and study changing blood flow in the skin.