--24.COMPUTERS:

Computer is an electronic device that can accept data,aaply a series of logical processess to it and supply the results of tehse processes as information.Computers are also used to perform a complex series of mathematical calculations at very great speed which makes them great for the numerous purposes.

KINDS:

The two main kinds of computers are

1.Analog computer
2.Digital computer.

in analog computer the numbers are represented by magnitudes of physical quantities as voltage,magnitudes etc.

The digital comouter is in which numbers are expressed directly as digits usually in the binary notion.The digital computers are howver more useful and versatile.

COMPUTER BASICS:

Computer is mainly based on
1.Hardware
2.Software
3.Input

Hardware consists of devices, like the computer itself, the monitor, keyboard, printer, mouse and speakers. Inside your computer there are more bits of hardware, including the motherboard, where you would find the main processing chips that make up the central processing unit (CPU). The hardware processes the commands it receives from the software, and performs tasks or calculations.

Software is the name given to the programs that you install on the computer to perform certain types of activities

Input is when we type a command or click on an icon, we tell the computer what to do. That is called input.

WORKING:

A computer is based on various components which when combined together perform useful functions.There is a CPU,the central processing unt which performs all the computations.It is supported by by memory which holds the current programme and data and logic arrays which helps in the provision and moment of information around the system.
The program and data ,text,figures and images or sounds are into in the computer which then processes the data and the outputs the results.

TYPES:

There are four main types of computers.
1.MICRO COMPUTERS
2.MINI COMPUTERS
3.MAIN FRAMES
4.SUPER COMPUTERS

Micro computers are the smallest and the most common an are used in small bussinesses,homes,schools.They are also reffered as home computers.
The mini computers are also known as personal computers and ar genrally larger and used in medium sized bussinesses and university departments.
The mainframes are found in alrge organizations companies and government departments in advanced countries mostly.

The super computers are the most powerful of all as they are especially used for highly complex scientific tasks as analyzing results of nuclear physics experiments and weather forecasting.


--25 SATELLITES:

Satellite technology has emerged tremendously over the last 50 years since Arthur C. Clarke first invented it. Today, satellite technology is all around us and has become a very useful, everyday application of modern telecommunications. Satellite systems can provide a variety of services including broadband communication systems, satellite-based video, audio, internet and data distribution networks, as well as worldwide customer service and support.

What is a satellite ?

An artificial satellite is a man made object placed into orbit around the Earth for the purpose of scientific research, weather reports, or military reconnaissance. Scientific satellites are set into orbit to observe the space environment, the Earth, the Sun, stars and extra galactic objects. These satellites have retrieved a huge amount of information helpful to scientific research. Weather satellites are used every day for meteorological forecasts and in shipping. Also military satellites play a important role in today's modern military. Satellites are extremely important today. All artificial satellites have certain features in common. They all include radar systems, sensors like optical devices in observation satellites and receivers and transmitters in communication satellites. Solar cells are used to generate power for the satellites and in some cases ,nuclear power is used. All satellites need altitude-control equipment to keep the satellite in the desired orbit.

Orbit of a Satellite

The orbit of the satellite is achieved when it is given a horizontal velocity of 17,500 mph at sea level causing the Earth's surface to curve away and as fast as it curves away gravity pulls the object downward and at this point the satellite achieved orbit. As the altitude of the satellite increases, its velocity decreases and its period increases. The period of satellite is the time the satellite takes to make on revolution around the Earth. Satellites in later orbit are called synchronous satellites. If the satellite orbits in a equatorial plane, it is called geostationary which means it is always over the same place on earth at all times. This form of orbit is used in weather for reports of a certain area at all times. The orbit of a satellite is very scientific but not hard to understand.

26.ANTIBIOTICS:

A chemical substance derivable from a mold or bacterium that kills microorganisms and cures infections.

Antibiotics are drugs used to kill or harm specific bacteria. Since their discovery in the 1930s, antibiotics have made it possible to cure diseases caused by bacteria such as pneumonia, tuberculosis, and meningitis - saving the lives of millions of people around the world.

But antibiotics must be used wisely. Because bacteria are living organisms, they are always changing in an effort to resist the drugs that can kill them. When antibiotics are used incorrectly, bacteria can adapt and become resistant. Antibiotics are then no longer useful in fighting them. Antibiotic resistance is now a major public health issue. The correct use of these drugs is the best way to ensure that antibiotics remain useful in treating infections.