What are the fundamental characteristics for the effectiveness of a data communications system?

The effectiveness of a data communications system depends on the following four fundamental characteristics.

What are the five components of a data communications system?

Data Communications: 

Data communications are the exchange of data between two devices using one or multiple forms of transmission medium. The devices are in need to be a part of a communication system made up of hardware and software.

Following are the five components of a data communications system.

Define molarity, molality, normality, mole-fraction.

Molarity (M): 

Molarity is defined as the number of moles of solute per litter of solution. That is,



Here,
     W = weight of solute.
     M = molecular mass of solute
     V = volume of solution

Show that the half-life of a second order reaction is inversely proportional to its initial concentration.

For the simple second order reaction 2A→product, we know the rate constant is given by,


For half life,  and 

Hence,




as k is a constant,


Derive an expression for the rate constant of 2nd reaction of the type, 2A→product.

2A → Product
initial concentration : a molL-1                       →                              0
final concentration (t=t) : (a-x) molL-1             →                  x molL-1



Integrating,

Derive an expression for the rate constant of a first order reaction. Give its units.

Let us consider a first order reaction,

A → product

Suppose at the beginning of the reaction, that is, when t=0, the concentration of A is amolL and when t=t, the concentration of A is (a-x)molL.

For a first order reaction, the rate of reaction,



where k is the rate constant.



integrating,





Here, c is the constant of integration.

Define order and molecularity.

Order:

Order of a reaction is defined by the number of atoms or molecules, whose concentration change during the reaction and determine the rate of the reaction.

For example,

It is a first order reaction.

It is a second order reaction.

What are the advantages of e-commerce?

E-commerce:

E-commerce or Electronic Commerce is a modern way of business. Transaction in case of buying or selling a product or service through electronic devices and internet connection is E-commerce. In E-commerce, the buyer and seller can not only communicate with each other but also the buyer can pay and the seller can receive payments through internet connection which can be called electronic payment service.

Here is a list of 12 Advantages of E-commerce.

What is e-commerce? Describe the features of e-commerce in detail.

E-commerce:

E-commerce or Electronic Commerce is a modern way of business. Transaction in case of buying or selling a product or service through electronic devices and internet connection is E-commerce. In E-commerce, the buyer and seller can not only communicate with each other but also the buyer can pay and the seller can receive payments through internet connection which can be called electronic payment service. So in E-commerce, a product travels to buyer from seller or a service is served to it's buyer without the need for the buyer to meet the seller by appearing physically. Again, in E-commerce, the seller receives payment for his/her sale without meeting the buyer physically.

How does a CRT monitor produces image on the screen?

Process of Producing Image on the Screen by a Color CRT Monitor:

A CRT monitor has an electron guns at its back. The gun fires an electron beams at once through a magnetic coil that aims the beams to the screen.

The screen is coated with a chemical called phosphors that glow when struck by electron beams. This phosphor coating is organized into grid of dots where smallest number of dots that can be focused by the magnetic coil at once is called pixel.