What are peripheral devices? What are the types of peripheral devices? Give Example.

Peripheral Device:

Those devices which are not required or essential for a computer system to boot and run are called peripheral devices. A computer system has four categories of computer hardware among which mostly all I/O devices are peripheral devices. Though there are other devices which are both input and output devices and most of them are peripheral devices. Along with these external and storage devices are also peripherals when the system already has its default storage and memory units.

Peripheral devices help in better use of the computer system, but the computer system itself can run without them.

Examples: Mouse, Keyboard, Sound System etc.

What are the characteristics of Fifth Generation Computers?

Fifth generation (future):

Computers from fourth generation are in use of everyday work. Japan and America is still trying to automate the system itself. Following are some of the characteristics of computers from fifth generations

What are the characteristics of Fourth Generation Computers?

Fourth generation (1971 - present):

The computers that we use now-a-days are the computers from fourth generation. From this generation more use of semi-conductors in memory started. Microprocessors has been created with LSI (Large Scale Integration) and VLSI (Very Large Scale Integration). The size and price of computers has both been reduced to significant levels. Followings are some of the characteristics of computers from fourth generation.

What are the characteristics of Third Generation Computers?

Third generation (1965 - 1971):

Use of integrated circuits (IC) started the third generation of computer which reduced the size, price, use of electricity etc. IC also facilitates speed and reliability of computers. Development of IC enabled organizing the whole central processing unit in single chip. Use of monitor also started in this generation. Operating system was improved to a new level and high speed line printers were in use. Followings are some of the characteristics of third generation. 

What are the characteristics of Second Generation Computers?

Second Generation (1959 - 1971): 

In 1947 transistors were invented, which was used in second generation computers to reduce the heat and size problem of the computers from first generation along with following characteristics

What are the characteristics of First Generation Computers?

First Generation (1951 - 1959):

Vacuum tubes were used to build computers of first generation. These computers were so large in size because of using thousands of diode, triode, transistors, capacitors etc. and also used to use a lot of electricity. These computers of first generation used to produce a lot of heat, so those were more expensive to support by setting up cooling systems. Maintenance of these huge sized computers were complex and expensive. Following are some of the characteristics of the computers of first generation.

How to know if an installed program is 32 or 64 bit in windows 10 64 bit

If you have installed a program and forgot in which platform it runs (32 or 64 bit) and you now need to find it out, then this tutorial is for you. 

Most of the programs now a days run on both of the platforms 32 bit and 64 bit. However, still there are few programs which run on either of these two platforms. If you have installed it and now need to figure out if it was a 32 or 63 bit then it's okay as there are many ways to find this out. Here we will discuss two methods to do just that.

What are the three types of transmission modes?

Based on the direction of data from sender to receiver, there can be 3 types of transmission modes which are discussed below.

What are the disadvantages of E-commerce?

Despite of the many advantages of E-commerce, there are some disadvantages of E-commerce. These disadvantages are minor and most of them will be no more with time and updates in technology. However, following are some of the disadvantages of E-commerce.

What are the three criteria necessary for an effective and efficient network?

A network must meet a certain number of criteria to become useable in real world situation. Most important of these criteria are the three criteria as follows.

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.

How does a color CRT monitor produces image on the screen?

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

A color CRT monitor has 3 electron guns at its back. These 3 guns fire 3 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.

What are the differences between Memory and Storage devices?

Though it may seem from the names that memory and storage devices are same thing, but actually they are far different. Following are the differences between Memory and Storage Devices.


How the computer accepts input for keyboard?

Keyboard is one of the most used input devices. Keyboard is a device with keys for alphanumeric characters along with various other keys to assist using the computer by sending instruction to the computer. The process of sending an instruction to the computer from keyboard when a key in the keyboard has been pressed is described below.


What are the four categories of computer hardware?

Computer Hardware: 

Hardware in a computer is any part of the computer that can be touched. These are primarily electronic devices used to build up the computer. Hardware actually perform the computing operations along with taking input and outputting the computed result or to store that.

There are four categories of computer hardware, they are being described below.

What is information processing cycle? What are the four phases of information processing cycle?

Information Processing Cycle:

The task of computer, in low level, is to process given data to produce information. Computer takes data, then processes the data as per being instructed and then can either output the generated information to user or store the information to storage or can do both. The generated information can be treated as data in the next cycle. These operations are part of a process called Information Processing Cycle which is a set of steps that computer follow to receive data, process the data and then either display the output to user or store the output to storage or do both.

What are the differences between system software and application software?

A system, such as: a computer, mobile or device like microwave oven, must need software to function. A software is a set of coded instruction for the system to execute in order to have it's hardware parts performing actions. However, software is primarily of two types, system software and application software.

How to make adsense ads responsive per screen size?

Yes, we can get responsive ad codes from adsense. But that will not fulfill the requirement for ad unit size per screen size. To make the adsense ads responsive per screen size we need to modify the code (allowed by google obviously) a bit. Reasons we need to do this can be like, In desktop view the ad appear as leaderboard, but in mobile it becomes a 300x250 square, what you might not want as you might want to show a similar horizontal sized ad in that place even in mobile view.

So let's see how we can do that.

How to write jQuery code before loading it?

jQuery and various other JS source files are regular part of website built nowadays. But this is always suggested to load JS files at the end of the document. In that case, how you are going to write JS code that requires jQuery to be loaded?

In one of my Web Development tutorial called 10 tips to speed up your website, I also suggested that you should load your JS files at the end of the document.

5. Put JavaScript at bottom:
This is also good practice in site optimization that you load your JS files just before your footer. This will let the browser draw the page without being blocked by JS files loading.

But the problem is, if you load jQuery at the end of the document and try to write jQuery code before that, you will get errors like $ is not defined. So how to write jQuery code before loading jQuery then!

Broadly discuss the measurements of price elasticity of demand.

Measurement of Price Elasticity of Demand: 

There are 5 different measurements of Price Elasticity of Demand. They are as follows:
  1. Perfectly Inelastic Demand (Elasticity = 0)
  2. Perfectly Elastic Demand (Elasticity = Infinity)
  3. Unit Elasticity of Demand (Elasticity = 1)
  4. Relatively Inelastic Demand (Elasticity < 1)
  5. Relatively Elastic Demand (Elasticity > 1)

These measurements has been discussed here. In the following discussion 5 symbols has been used which are

10 Tips on CSS: The Right Way

We know how important CSS is in case of developing UI in web projects. But most of the time we don’t take it seriously. When we are asked to create PSD to HTML, we simply start writing our HTML and CSS. We do not examine the complete PSD to find out similarly styled elements, similarly styled elements with very view changes such as with border radius and without border radius, floated at left and floated at right etc. Instead of examining the full PSD to find out this kind of design patterns we start writing CSS from TOP to BOTTOM.

I would say, that is a very bad practice.


Find the value of half-life period.

Value of Half-Life Period


From the law of radioactive disintegration, we know,


If,  be the half life period, then at, 



Deduce the law of radioactive disintegration.

The Law of Radioactivity Disintegration:

Let, N be the number of atoms present in the radio element at a given instant t. Then the rate of decrease,


Here, λ is the disintegration constant. It is defined as the ratio of the amount of the substance which disintegrates in a unit time to the amount of substance present.


Describe the general properties of nucleus.

General Properties of Nucleus:


(i) Nuclear Size:

From Rutherford’s work, the mean radius of nucleus is  and the radius of the atom is . Thus the radius of the nucleus is 10,000 times smaller than the radius of the atom.

The empirical formula for the nuclear radius is,


Here, A is the mass number,  is a constant.


From this formula the radius of the Carbon () nucleus is.




Derive the de Broglie wavelength for a charged particle of charge q and accelerated through a potential difference of V volts.

The Required de Broglie Wavelength:

A photon of light of frequency  has the momentum,


But, . Therefore, the momentum of the photon can be expressed in terms of wavelength λ as,


The wavelength of a photon is, therefore, specified by its momentum according to the relation,


Derive the Einstein’s photoelectric equation.

Einstein’s Photoelectric Equation : 

According to Einstein, light of frequency  consists of a shower of photons, is of energy . When a photon of light of frequency  is incident on a metal, a part of the energy acquired by the electron is used to pull out the electron from the surface of the metal and the rest of it is utilized in imparting K.E. to the emitted electron.

What do you mean by electric flux or flux of the electric field?

Electric Flux

For an arbitrary closed surface, the net outward flow or flux is the product of the average outdrawn normal component of the vector and the area of surface. Electric flux is used to express the relation between  and its source. Flux is denoted by 

 = (average normal component)×(surface area)

The unit of electric flux is newton-meter2/coul.

What is flux?

Flux

If  is a vector field, then the flux through any face is defined as the scalar product of the vector area of the face and the vector . That is,

Flux = (component of velocity normal to the face) × (area of the face)
         
The amount of flux per unit area is defined as the divergence of the vector 

What is electric charge?

Electric Charge

The reason present in a material causes static electricity, electric field in the material and the material become able to attract other materials is called electric charge. It may be positive or negative. Unit of electric charge is coulomb (C).

What are dextrorotatory and laevorotatory substances?

Dextrorotatory and laevorotatory substances are optically active substances.

Dextrorotatory  substances

Substances which rotate the plane of polarization of the light towards the right are known as dextrorotatory substances.

Laevorotatory substances

Substances which rotate the plane of polarization of the light towards the left are known as laevorotatory substances.

What is optical activity?

Optical activity

Optical activity is the ability of a substance to rotate the plane of polarization of plane polarized light. Substances which have this ability are called optically active substance. Tartaric acid is an example of optically active liquid.

What is nicol prism?

Nicol prism

Nicol prism was invented by William Nicol in 1828. It is an optical device used for producing and analyzing plane polarized light. The nicol prism is made in such a way that it eliminates one of the two rays by total internal reflection. It is generally found that it eliminates the ordinary ray and only the extraordinary ray is transmitted through the prism.

What do you understand by double refraction?

Double refraction

Erasmus Bartholinus discovered in 1669, that, when a ray of light is refracted by a crystal of calcite it gives two refracted rays. This phenomenon is called double refraction. Calcite is crystallized calcium carbonate (CaCO3). It crystallizes in many forms and can be reduced by cleavage or breakage into a rhombohedra.

Define phase velocity and group velocity?

Phase velocity

Phase velocity is the velocity with which a plane progressive wave front travels forward. Phase velocity is symbolized by . It has a constant phase = 

Group velocity

The group velocity () is the speed with which the point of reinforcement of the resultant wave travels. The group velocity is different from the individual wave velocity.

What do you mean by phase angle and epoch?

Phase angle

Phase angle is defines as the fraction of the time interval that has lapsed since the particle has crossed the mean position of rest in the positive direction. It is also equal to the angle swept by the radius vector since the vibrating particle last crossed its mean position of rest.