PHYSICS FOR BEGINNERS

 Muhammad Idrees

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LED'S 

Light emitting diodes, commonly called LEDs. They do dozens of different jobs and are found in all kinds of devices. Among other things, they form numbers on digital clocks, transmit information from remote controls, light up watches and tell you when your appliances are turned on. Collected together, they can form images on a jumbo television screen or illuminate a traffic light.

Basically, LEDs are just tiny light bulbs that fit easily into an electrical circuit. But unlike ordinary incandescent bulbs, they don't have a filament that will burn out, and they don't get especially hot. They are illuminated solely by the movement of electrons in a semiconductor material, and they last just as long as a standard transistor. The lifespan of an LED surpasses the short life of an incandescent bulb by thousands of hours. Tiny LEDs are already replacing the tubes that light up LCD HDTVs to make dramatically thinner televisions.

In this article, we'll examine the technology behind these ubiquitous blinkers, illuminating some cool principles of electricity and light in the process.


BREADBOARD AND MINI ELECTRONICS PROJECTS?

A breadboard is a temporary circuit board for testing and designing circuits, no soldering is done on the board. It is faster and easier to experiment on a breadboard than it is to solder (fuse in to place) circuit components. In the mini electronics projects, you gain hands-on experience building and testing electronic circuits by creating a breadboard circuit with a resistor, a light-emitting diode (LED) , and a battery. The LED will light up when the circuit is closed or completed. This basic exercise will help prepare you for more advanced electronics projects....


CURRENT & ELECTRICITY

If you've ever sat watching a thunderstorm, with mighty lightning bolts darting down from the sky, you'll have some idea of the power of electricity. A bolt of lightning is a sudden, massive surge of electricity between the sky and the ground beneath. The energy in a single lightning bolt is enough to light 100 powerful lamps for a whole day or to make a couple of hundred thousand slices of toast!
What is electricity?

Electricity is a type of energy that can build up in one place or flow from one place to another. When electricity gathers in one place it is known as static electricity (the word static means something that does not move); electricity that moves from one place to another is called current electricity.
When electrons move, they carry electrical energy from one place to another. This is called current electricity or an electric current. A lightning bolt is one example of an electric current, although it does not last very long. Electric currents are also involved in powering all the electrical appliances that you use, from washing machines to flashlights and from telephones to MP3 players. These electric currents last much longer.
Static electricity and current electricity are like potential energy and kinetic energy. When electricity gathers in one place, it has the potential to do something in the future. Electricity stored in a battery is an example of electrical potential energy. You can use the energy in the battery to power a flashlight, for example. When you switch on a flashlight, the battery inside begins to supply electrical energy to the lamp, making it give off light. All the time the light is switched on, energy is flowing from the battery to the lamp. Over time, the energy stored in the battery is gradually turned into light (and heat) in the lamp. This is why the battery runs flat.

GREENHOUSE EFFECT
The Earth is wrapped in a blanket of air called the 'atmosphere', which is made up of several layers of gases. The sun is much hotter than the Earth and it gives off rays of heat (radiation) that travel through the atmosphere and reach the Earth. The rays of the sun warm the Earth, and heat from the Earth then travels back into the atmosphere. The gases in the atmosphere stop some of the heat from escaping into space. These gases are called greenhouse gases and the natural process between the sun, the atmosphere and the Earth is called the 'Greenhouse Effect', because it works the same way as a greenhouse. The windows of a greenhouse play the same role as the gases in the atmosphere, keeping some of the heat inside the greenhouse.
The GREENHOUSE GASES are very important and are mainly:
Water vapour H2Og
occurs naturally in the atmosphere.
Carbon dioxide CO2
produced naturally when people and animals breathe. Plants and trees absorb carbon dioxide to live. Volcanoes also produce this gas. Carbon dioxide is not the same as carbon monoxide.
Methane CH4
comes from cattle as they digest their food. The gas also comes from fields where rice is grown in paddy fields.
Nitrous oxide HNO2
when plants die and rot, nitrous oxide is produced.
Ozone O3
occurs naturally in the atmosphere.

 Schrödinger Atomic Model


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