Answer:
ptic fiber communication and satellite communication are the leading technologies which are revolutionizing the world of telecommunications. Both technologies have their advantages and limitations which make them suitable for certain type of applications. This article will provide an overview of optic fiber and satellite communication technologies and present a comparison of the features and related issues.
Optic Fiber Communication
Optic Fiber communication transmits information by sending pulses of light (using laser) through an optic fiber. The low signal loss in optic fibers and high data rate of transmission systems, allow signals with high data rates (exceeding several Gbps) to travel over long distances (more than 100 km) without a need of repeater or amplifier. Moreover, using wavelength division multiplexing (WDM) allows a single fiber to carry multiple signals (upto 10 different signals) of multi-Gbps transmissions. Optic Fiber communication offers extremely high bandwidth, immunity to electromagnetic interference, non-existent delays and immunity from interception by external means. In the 1980s and 1990s, the continents were linked together using undersea optic fiber bringing about a paradigm shift in the global telecommunications.
These advancements in optic fiber communication has resulted in decrease of satellite communications for several types of communications. For instance, transmission between fixed locations or point-to-point communications, where large bandwidths are required (such as transoceanic telephone systems) are made through optic fiber instead of using satellite communication. Optic Fiber communication is also used to transmit telephone signals, Internet communication, LAN (Gigabit LAN) and cable television signals.
Satellite Communication
Satellite communications use artificial satellites as relays between a transmitter and a receiver at different locations on Earth. Satellite systems allow users to bypass typical carrier offices and to broadcast information to multiple locations. Communications satellites are used for radio, TV, telephone, Internet, military and other applications. There are more than 2,000 satellites around Earth’s orbit, being used for communication by both government and private organizations.
Communication Satellites are LOS (line-of-sight) microwave systems with a repeater. These satellites rotate around the earth with the speed of earth and are known as geostationary satellites. The limitations of antenna size also limits focusing capability making the coverage for a single satellite transmitter very large. This makes satellite communication ideal for TV and radio services as the signal has to flow from a single point to many points in a single direction. The large distance of satellites from the earth (about 22,300 miles) results in delays which adversely effects two-way communication like mobile conversations. Low earth orbit satellites can be used for two-way mobile communication because less power is required to reach those satellites.
Explanation:
the temperature is decreased
Answer:
14.6 g of barium phosphate
3.35 g of sodium metal
Explanation:
2Na3PO4(aq) + 3Ba(s) -------> Ba3(PO4)2(aq) + 6Na(s)
The first step in any such reaction is to but down the balanced reaction equation according to the stoichiometry of the reaction.
The two products formed are barium phosphate and sodium metal.
Number of moles of barium corresponding to 10.0g of barium = mass of barium/ molar mass of barium
Molar mass of barium = 137.327 g
Number of moles of barium = 10/137.327
Number of moles of barium = 0.0728 moles
For barium phosphate;
3 moles of barium yields 1 mole of barium phosphate
0.0728 moles yields 0.0728 moles × 1/3 = 0.0243 moles of barium phosphate
Molar mass of barium phosphate = 601.93 g/mol
Therefore mass of barium phosphate = 0.0243 moles × 601.93 g/mol = 14.6 g of barium phosphate
For sodium metal
3 moles of barium yields 6 moles of sodium metal
0.0728 moles of barium yields 0.0728 × 6 / 3 = 0.1456 moles of sodium
Molar mass of sodium metal= 23 gmol-1
Mass of sodium metal= 0.1456g × 23 gmol-1 = 3.35 g of sodium metal
Answer:
It is due to the nature of the reactants
Explanation:
To ignite a solid, we require more heat component compared to liquids and gases. For ignition to occur, oxygen gas combines with a reactant in most cases.
Some factors affect the rate rate at which a chemical proceeds. One of the factors is the nature of reactants.
The solid phase is very slow while the gaseous phase is rapid and fast.
solid phase < liquid phase < gas phase
Gases are free and the molecules move in all direction. They easily combine and react very fast.
