ELECTROMAGNETIC RADIATION

ELECTROMAGNETIC RADIATION

The World Health Organization (WHO) defines electromagnetic fields on its Webpages dedicated to the concerns regarding the increasing presence of this form of radiation. In essence, an electromagnetic field is comprised of two components, one being an electric field generated by differences in voltage and another being a magnetic field generated by the flow of current. The field propagates at the speed of light (300,000 kilometers per second or 186,000 miles per second) in waves of a certain length that oscillate at a certain frequency (number of oscillations or cycles per second). In the electromagnetic range, gamma rays given off by radioactive materials, cosmic rays, and X-rays are all dangerous to humans and other organisms because of the relatively high energy "quanta" (packets) they carry (high frequency or short-wavelength waves). Such rays lead to "dangerous radiation" (ionizing; i.e., with an ability to break bonds between molecules). Mobile phone systems also act in the electromagnetic range (sometimes referred to as "microwave" or "radio frequency"), however, the frequency (energy "quanta") of the longer-wavelength waves associated with this technology is lower (and therefore safer to humans) and regarded as "non-ionizing".

TYPES OF ELECTROMAGNETIC RADIATION

Ionizing radiation -

 This type of radiation contains enough electromagnetic energy to strip atoms and molecules from the tissue and alter chemical reactions in the body. Gamma rays and X-rays are two forms of ionizing radiation. We know they cause damage, which is why we wear a lead vest when X-rays are taken of our bodies.

Non-ionizing radiation -

Non-ionizing radiation is typically safe. It causes some heating effect, but usually not enough to cause any type of long-term damage to tissue. Radio-frequency energy, visible light and microwave radiation are considered non-ionizing. Electromagnetic Spectrum

Infrared detection in animals

Infrared detection in animals

Vision is defined by its access to the visible electromagnetic spectrum. Many animals, notably insects and birds, can see into the ultraviolet, although this comes with the concomitant dangers that these short wavelengths (10-400 nm) are high energy and potentially biologically destructive. At the opposite end of the visible spectrum are orange and red, and there has been considerable speculation whether any optical system could register infrared, drawing upon a suitably adapted opsin. The reason to be sceptical is that the radiation of these long wavelengths (750 nm-1 mm) is of low energy, and indeed to date there is no direct evidence for infrared vision. We can, of course, sense it as radiant heat, but several times animals have independently evolved systems of infrared detection that in a number of respects are closely analogous to the eye. In a variety of organisms, transducers process incoming infrared radiation into a sensory signal that is interpreted by the brain and in at least one case (the snakes) is integrated with visual information. Unsurprisingly, infrared detection is ultimately involved with heat sources, but these can vary from 'warm-blooded' prey (snakes, vampire bats and bed bugs) to forest fires (three independent examples in the beetles)

Infrared detection in vertebrates

Infrared detection in insects

Read more @

http://www.mapoflife.org/topics/topic_311_Infrared-detection-in-animals/

What is the difference between 'charge' and electron/proton?

What is the difference between 'charge' and electron/proton?

The unit of charge (called Coulombs, after the physicist who coined it) was developed before people knew about electrons and protons. When they discovered the source of the charge, they measured how much of the already established unit of charge was carried by a single electron.

Since for most purposes, there are lots and lots of electrons involved, it's easier to use the older system. However, there is another system where the charge of an electron is 1e (e being the unit of electron charge).

Different units are used for different purposes. The natural units system relies on setting fundamental constants to 1 unit and bases everything else off that. e is the charge of an electron. c is the speed of light, and h is plank's constant. In quantum mechanics, where they deal with individual atoms, these units are often used instead of meters, seconds, coulombs, kilograms, etc.

Charge
- there are two kinds of charge, positive and negative
- like charges repel, unlike charges attract
- positive charge comes from having more protons than electrons; - - negative charge comes from having more electrons than protons
- charge is quantized, meaning that charge comes in integer multiples of the elementary charge e
- charge is conserved

Resistors /ohms law ,what is electronics

what is electronics?

The branch of physics and technology concerned with the design of circuits using transistors and microchips, and with the behaviour and movement of electrons in a semiconductor, conductor, vacuum, or gas.

Resistors /ohms law

Resistors come under passive electronic components and are extensively used in electronic circuits. So important are these components that it may be virtually impossible to build an electronic circuit without involving resistors. Basically the function of a resistor is always to oppose the flow of current through it and the strength of this opposition is termed as its resistance. German physicist, Sir G.S. Ohms was able to discover a definite relationship between voltage, current and resistance. According to him a potential difference or a voltage (V) across a resistor (R) is proportional to the instantaneous current (I) flowing through it .and is given as:

V = R.I

Here R is the constant of proportionality and is known as the resistance of the resisto

GSM based remote equipment control systems using micro controller

GSM based remote equipment control systems using micro controller

ABSTRACT

               Now a day's every system is automated in order to face now a day's every system is automated in order to face new challenges in the present day situation. Automated systems have less manual operations, so that the flexibility, reliabilities are high and accurate. Hence every field prefers automated control systems. Especially in the field of electronics automated systems are doing better performance.                              

                 Probably the most useful thing to know about the global system for mobile communication is that it is an international standard. If you travel in parts of world, GSM is only type of cellular service available. Instead of analog services, GSM was developed as a digital system using TDMA technology.

              The goal of the project is to develop a system, which uses GSM Mobile technology that keeps control of the various units of the automobiles, which executes with respect to the signal sent by the mobile.

                     For utilization of appliances the new concept has been thought to manage them remotely by using GSM, which enables the user to mobile control switching security system of industrial appliances. Just by sending SMS of mobile cell phone, from where you are calling you can perform ON / OFF operation of the appliances.     

                        

                     The ranges of appliances that can be controlled through GSM mobile systems are many in numbers.  Some of them are as follows and this depends upon the usage priority of the appliances i.e. parking Lights, Music System or other electrical / electronic appliances.

SPECIFICATIONS:

Applications:

§  In communication based applications.

§  Communication for further applications

Advantages:

§  There will be continuous observation on parameters.

§  Highly reliable.

§  Ease of operation.  

  Technologies Involved:           

§  Micro controller

§  GSM

   Software tools:

§  C  code

§  Embedded C

§  HI-TECH PICC

§  Express PCB