Forms of Heat Transfer

Introduction to forms of heat transfer
The science of heat transfer is concerned with the estimation of the rate at which heat is transferred, the duration of heating or cooling for a certain heat duty and the area required to accomplish that duty.

There are three different forms of heat transfer : 1. conduction 2. convection 3. radiation

Conduction form of heat transfer

It is the  heat transfer between two bodies or two parts of the same body through molecules which are more or less stationary. In liquids and gases conduction results from the transport of energy by molecular motion near the wall and in solids it takes place by a combination of lattice vibrations and electron transport. The law which determines this conduction heat transfer is called as Faraday's Law. This law states that the rate of heat flux is linearly proportional to temperature gradient.

Convection Form of Heat Transfer

It is the heat transfer that occurs because of the motion of a fluid past a heated surface - the faster the motion, the greater the heat transfer.  The convection heat transfer is usually assumed to be proportional to the surface area in contact with the fluid and the difference in temperature of the surface and fluid. This is also called as Newton's law of convection. When a temperature difference produces a density difference which result in mass movement, this process is called as free or natural convection. When the mass motion of fluid is caused by an external device like a pump, compressor, blower or fan, the process is called the forced convention. Here the fluid is made to flow along the hot surface and heat is transferred from the wall to the fluid.

Radiation Form of Heat Transfer

It is the heat transfer which is the result of electromagnetic radiation emitted by a surface because of the temperature of the surface. This differs from other form of electromagnetic radiation such as radio, television, X-rays, Gamma rays which are not related to the temperature.The best example of this is the heat receiving from the sun. The laws which govern this type of heat transfer are:

a. Kirchhoff's law

b. Stefan's law

c. Stefan- Boltzmann's law

Diffraction Limited

An introduction to diffraction limited:

The ability to produce images of an optical system with the angular resolution after overcoming the imperfections of the lenses is called as diffraction Limited. The optical instruments like Telescope, Microscope and camera are said to be Diffraction Limited if they give enough accuracy. Let us discuss more on diffraction limited. I like to share this Define Emp with you all through my article.

Discussion on Diffraction Limited

In Physics this Diffraction -Limited of the instrument is independent of imperfection due to other substances. It depends only on the limit of the optical power of the instrument. Like the diffraction of the telescope does not depend on the turbulence of the atmosphere. The resolution of an instrument is proportional to the size of the object and inversely proportional to the wavelength of the observed light. For telescope of circular apertures, size of the smallest feature in an image that is diffraction limited is size of the airy disc. One more important term is there to describe this topic better is Rayleigh’s limit. Rayleigh’s limit is the telescope’s ability to separate closely situated stars. The visual Rayleigh’s limit for a 203mm aperture telescope is 0.69arc seconds. Another limit is Dawes Limit that is 0.57arc second. The accuracy of radio telescope is much higher than normal telescope because they use very long wavelength which minimize the atmospheric distortion. Please express your views of this topic Formula of Density by commenting on blog.

Techniques on Diffraction Limited

The two techniques are there for diffraction limit, they are near field technique and Far field technique.

Near field technique- The Near field technique is applied for light of less than 2 wavelength.This technique gives that information beyond Diffraction –Limit.It is used to construct very high resolution image .It is used in total internal reflectance microscopy and metamaterials.It gives better result by placing objective lens extremely close to the object.As Near field technique cannot give the image more than 1 wavelength, so it can’t use in thicker than 1 wavelength. That’s why the practical uses of this technique are rare.

Far Field Technique-This is the best technique to use for imaging objects having large wavelength. It uses in biological applications like cells. This technique usually exploit optical non-linearity in material’s reflected light to generate resolution beyond the diffraction limit.

Conclusion for Diffraction Limited

A Laser beam is also called Diffraction Limited if its beam quality is ideal. In that case the laser beam focused to a small spots is as high as possible for the given wavelength. For advice on how to measure the beam quality of your laser source, or how to optimize.

Kinetic Theory

Kinetic Theory of Matter Definition : We Define Kinetic Theory as explanation which predicts the behavior of matter or motion of its particles on certain assumptions and observations.  The Kinetic Theory of Matter considers that matter is composed of very small particles or molecules which are always in motion. The Kinetic Theory gives the difference between the three elementary states of matter. This theory assumes that the matter is composed of small particles, particles are in constant or continuous motion.
Solid matter consists of particles which are so closely packed that they can vibrate only but cannot move.  In liquid matter particles are little far from each other but still close enough that the force of attraction that it takes the shape of container. The movement of the particles in liquid is confined in the volume of liquid. In gaseous matter the particles are free to move, they are very far from each other and have large kinetic energy. I like to share this Average Kinetic Energy Formula with you all through my article.

Because of the random movement, particles (liquid and gas) collide with each other and with the walls of container.  The collision between particles takes place without any change in net energy but exchange energy among them. Hence collision is perfectly elastic.
The movement of particles decides their kinetic energy through formula: KE=½mv2, m is mass and v is velocity of particle. This kinetic energy of particles decides the thermal energy or temperature of the matter. Temperature is actually the average kinetic energy of the particles of a matter.
Transfer of heat takes place from a matter of high temperature to low temperature. High temperature particles move or vibrate with high speeds and when they collide with nearby particle of less temperature (less KE), they exchange KE to them (hence increases temperature of neighbor particles). Now these particles start vibrating or moving fast and gives energy to their neighbor particles and so on. Hence thermal energy transfers from high to low temperature. So, kinetc theory explains the flow of heat by conduction which is flow of heat-energy through a matter. I have recently faced lot of problem while learning Activation Energy Formula, But thank to online resources of math which helped me to learn myself easily on net.

Kinetic Theory of Gas says that a gas consist of large number of very small particles of same mass which move continuously and randomly with certain speed. These particles collide perfectly elastically with each other and with the walls of the container.  It explains the properties, temperature, pressure and volume of gas.
Pressure due to particles on walls=(Nm2)/(3V)
Temperature T= (m2)/(3kB)
Kinetic energy=½Nm2
is average velocity of particles, N is no. of gas molecules,V is volume, m is mass of molecules, kB is Boltzmann constant.

Water Vacuum Pump

Introduction to the water vacuum pump:

A pump works by displacing a volume of liquid or gas by physical or mechanical action.

A vacuum pump is a mechanism that displaces gas molecules from a sealed chamber to form a partial vacuum. Understanding Wavelength of Light Formula is always challenging for me but thanks to all math help websites to help me out.

In 1650 vacuum force was first discovered by Otto von Guericke in an experiment where air was removed from a sealed chamber, thereby its space became a vacuum. This led to the invention of the vacuum pump.

Working of a Manual Water Vacuum Pump

As fluids cannot be drawn up, it is impossible technically to create a vacuum by suction. Artificial vacuum can be created by increasing the volume of a container.

The principle behind a manual water pump like positive displacement pumps,is to continuously evacuate a chamber to create a compartment of vacuum by repeatedly closing and expanding. A handle expands a sealed cavity to create a deep vacuum  and due to the pressure difference, fluid from outside is pushed into the pump's small cavity. This is then sealed from the chamber by the handle, opened to the atmosphere to let the fluid move out.

The handle is the mechanism which acts as suction and discharge valves to ensure that the fluid moves in a upward direction.

Types of Vacuum Pumps

As per the method of moving a fluid, pumps can be grouped as direct lift, velocity, displacement,gravity and buoyancy pumps. I have recently faced lot of problem while learning Work Word Problems, But thank to online resources of math which helped me to learn myself easily on net.

The three main types of vacuum pumps- are electromechanical pumps, compressed air pumps and entrapment pumps. By forcing gas molecules through a nozzle, compressed air pumps increase the pressure of a gas by decreasing the space within thus creating a vacuum effect. Electromechanical pump which run on electricity creates a vacuum effect by trapping air inside the rotors and then pushing it out. Entrapment pumps take in gases and hold them in a sealed chamber.

Conclusion to Water Vacuum Pump

The pump housing or the vacuum chamber, is filled with water. When the pump is on, its motor drives an impeller at the other end at a high speed thus creating a vacuum to pull the water upwards. A diffuser is needed to release the air out of the pump or suction piping.

Types of Radio Communication

Introduction to Types of radio communication

Radio communication is the transmission of radio signals. These signals are electromagnetic frequencies. The frequencies are modulated for communication and they are less than the frequency of visible light.

These electromagnetic radiations travel through air and vacuum. In order to carry the information, some of the properties are modulated, or changed. The properties of radio waves are amplitude, phase and frequency. I like to share this Wavelength Color Spectrum with you all through my article.

About Types of Radio Communication

Radio waves are non-ionizing radiation.  The frequency of the radio waves differs for different applications:

1. Radio for audio: Amplitude modulation is used to transmit audio signals from one place to another through air or vacuum. There is a transmitter for transmitting signals and a receiver at receiving end to absorb signals.

2. Telephony: the cell phone communication uses radio signals. Earlier phones used frequency modulation; however some of the recent technologies are digital modulation of radio waves.

3. Video: the television signals are transmitted as radio signals. These signals are sent with amplitude modulation for video and FM or AM for sound. The frequency of video radio waves is 4.5 MHz

4. Navigation: satellite navigation systems use radio signals to communicate. A satellite transmits the signals and based on the position of the satellite and the tangential line around each satellite, the computer that receives the signal calculates and determines the position.

5. Heating: radio frequencies are used to generate heat inside generatingequipment. Microwave ovens use radio waves for heating food. Surgery equipment diathermy uses radio frequency for sealing blood vessels. Several induction furnace use radio waves for melting metals.

6. Amateurradio: this radio offers several frequencies for amateurs who are licensed to communicate.

7. Radar for radio detection and ranging uses radio waves for detecting objects at a distance

8. The recent addition is the radio signals for transmission of digital data.



Conclusion for Types of Radio Communication

Radio waves are transmitted through air or vacuum for various purposes by modulation in the properties. They do not charge the particles of the medium they travel through. The frequency range of radio is between a few hertz to three hundred gigahertz. There are several types of radio communication used for all the above discussed purposes.

Frequency of Periodic Motion

Introduction to frequency of Periodic Motion

The number of cycle accomplished for each second. The element used instead of cycles for every second is hertz. The fraction of a period finished for all units travel as of left in the direction of right. Frequency is the reciprocal of time. Such as graph through time, 8 contain frequency 1/8. Specifically,1/8 of a time which mean for every unit travel as of left in the direction of right. I like to share this Frequency and Wavelength Formula with you all through my article.

Frequency Periodic Motion
Periodic Motion

Motion that is repeats itself identically more and more. For example, alternation of a pendulum. But the motions exist to model with a sinusoid; it is called uncomplicated harmonic motion.

Periodic Function

Functions which contain a graph to repeat itself identically in excess of which it follows as of left in the direction of right. Properly, a function f be cyclic but the present exists a number p such that f(x + p) = f(x) for every x.

Period of Periodic Motion

This occasion is required for an absolute cycle. Such as, pendulum which moves in a periodic motion. Period be the occasion to use for the pendulum that moves backward and forward as of one side in the direction of left to right and right to left when it reverses again.

Pendulum Exhibits Periodic Motion

Pendulum consider of a weight hanging on a scheduled rod, wire. While the weight is enthused also allow go away, the pendulum determination move backward and forward back also onwards within a usual cyclic motion. The change of gravity lying on the move up and down consequences within the intervallic motion with its length determines the rate of its swing. Pendulums enclose been use in clocks used for hundreds of days, since the motion is thus normal. Please express your views of this topic coulomb's law problems by commenting on blog.

Example

Periodic Motion

Motion to repeat itself within equivalent interval of instant be called Periodic Motion. The motion of a vibrate body as of individual excessive end in the direction of the further excessive point also reverse near the first excessive point be call vibration.

For instance the movement of the move up and down of effortless Pendulum as of A in the direction of B also reverse as of B in the direction of A through point "O" is call one Vibration.

Time period

Time necessary near absolute single vibration be call Time Period of vibrate body. The time period is represented by “T".

Frequency

Number of vibrations execute through a vibrating body within single second be called its frequency.The frequency id denoted by f.

Tensile stress formula

When a material is exposed to a pull or stretch, it is said to be under tensile stress. Tensile stress is a type of stress that occurs when a material under stress is elongated or stretched due to the applied force. It is calculated by dividing the applied force by cross sectional area of the material on which the force is applied. Since a material is said to be under stress when a force is applied on its cross sectional area and result is its stretching or pulling. Hence the tensile stress formula can be expressed as
Tensile stress=F/A
Here F=applied force
A=cross sectional area of the material on which the force is applied.
Here force is measured in Newton and the cross sectional area is measured in mm2, hence unit of tensile stress is N/mm2. Having problem with Define Unbalanced Force keep reading my upcoming posts, i will try to help you.

What is the definition of stress
Let’s assume that force is applied to an elastic body. The applied force will cause change in its shape and size. We say that the body is deformed. This is because the body or material is under stress. Stress can be defined as force applied on unit area of the material. Depending on the type of force, the elastic material will compress or elongate.

stress definition
Stress is the measurement of force applied on unit area of a material. It is measured in Pascal which is expressed in Newton per m2
stress equation
Since stress is measurement of force applied on cross sectional area of a material, its equation is expressed as following:
Stress=force/cross sectional area on which the force is applied. Here stress is symbolised by “sigma” s.
equation for stress
Equation for stress includes force and area of the material. It is expressed as
s=F/A
Here  s=stress
F=force
A=area of material under force.
Here we assume that force is applied equally all over the length of material. But practically we calculate the stress by measuring the force felt at the end of the length of material. Please express your views of this topic Elastic Potential Energy Formula by commenting on blog.

stress vs strain curve
As we know that a material under stress will be elongated or compressed, depending on the type of applied force. Suppose a material is subjected to tensile force. If we draw the force-extension graph for the material, it will show the behaviour of the material under force. Here we should remember that different materials will show different extension behaviour, even if they are exposed to same force. This is due to the fact that extensibility of a material depends on its shape, dimensions and many other factors. Hence the force-extension graph, that show the extension behaviour of material irrespective of their dimensions, are known as stress=strain curve.