Solar Energy

I am sure solar energy requires no introduction. Today India is being rocked by issues like the Nuclear proliferation treaty, coal scam etc. These are primarily because of the impending energy crisis that the world will come face to face with soon enough. And India is going to be one of the worst affected as it is one of the most densely populated countries. We recently got a glimpse of what might happen when fossil fuels get exhausted when there was a massive grid failure in the northern parts of the country. It was because of the fact that some of the states drew more than excess power that caused the generators to slow down thus disrupting the entire grid. It exposed the country’s dependence on fossil fuels only and the impending need to promote renewable energy sources. Sadly our policy makers are not too concerned with tapping alternative energy sources while all efforts to do so(nuclear power) is met with opposition for petty politics.
However there are plenty of other sources as well. While hydel power is a prospective source of energy in India it is consequential because it can damage fragile ecosystems and displace entire populations. Then naturally Solar energy seems to be the logical choice.
So what’s stopping them from adopting solar energy?
Two things:
a) Cost
b) Erratic supply
a) Cost
Yes like any other new product in the market costs determine how effectively it can be implemented. The biggest problem with solar energy is that it is very expensive. Yes it takes about 2000$ just to install solar Photovoltaic(PV) modules plus even in the well developed sunny states of the U.S. the cost of solar cells is about 0.11$ / kWh. Now that really is expensive if you compare it in the Indian currency.
b) Erratic supply
Yes it is true that India has a huge amount of solar radiation input being in the tropics and everything working out to be fine India should be having more than enough energy to compensate for the energy needs of the country. BUT we should also try to remember that India is a place where the monsoons cover the Indian skies with clouds for a considerable part of the year too. This does deter the energy supply and this would have been a cause of great distress among the millions as energy demands are high and an uninterrupted supply is necessary in many parts of the country. Plus supply during the night time would be a huge problem as there is no effective way to store energy obtained during the day.
But what exactly is  a photovoltaic cell?
A photovoltaic cell uses photons from the sun’s energy spectrum and converts it into kinetic energy of electrons.

It has an antireflective coating at the top to remove any sort to prevent loss of solar energy by reflection. As can be seen from the diagram, The photons strike the electrons at the junction of the p type and n type semiconductors to create a voltage difference. This voltage causes a current to flow in the closed circuit.
If solar energy needs no investment other than maintenance to continue then why should the initial high cost be a problem?
Well the problem comes from the fact that efficiency of solar PV cells is very small. Typical energy efficiencies are about 8 to 10% today. In fact all the major corporations of the world are working on increasing efficiencies as you read this article.

As you can see the technology used increases efficiency a lot. But what is not mentioned here is that the cost of increasingly complex technology is quite high. Efficiency determines the fate of new technology as solar pv cells are no exception.
But that does not mean that solar energy does not hold promise. For it has been calculated that the amount of solar radiation the earth receives at the sea level is more than enough to supply 8 times the energy requirements of the World’s population.

Career Prospects in the field of Statistics and Economics

What are career prospects in the field of Statistics and Economics?

Economics being a social science is considered to be very vital in analyzing the effects of production, sales including consumption of goods on the economy of the user or the common man. The concept of economics is applied in every field; be it an industry, agricultural sector, banking sector, labor sector the principles of economics has a dominant role to play. In fact many of the leading industries including banks engage the services of economists to advise the industry or the organization on many of the policy matters including those involving production and matters relating to financial propriety and a host of other relevant issues. Every government will engage the services of economists to advise the government on various issues concerning the government policies on price control, banking regulation and such other related matters.

Those who aspire to take up economics as a career have the option to take up diploma course in economics. However, from the career prospects the diploma course may not be much feasible. Therefore, it is advisable that they take either graduate or postgraduate course in economics. As already mentioned in economics there are several areas of specialization like for example agricultural economics, industrial economics etc. Therefore depending on the specialization the career can be preferred. Remember, your opinion as an economic adviser has great value in terms of forming the future policies of the organization. Therefore it is a very prestigious and equally a responsible position.

A statistician is the person who works out with the data available all around us and as one expert puts it he ‘churns out’ the result. With his innovative approach and scientific principles he draws conclusions to various issues and it forms the basis for your policy making and plan future course of action. Every organization and particularly industries and the government need statistical data to regulate their work and also take effective policy decisions. Similar to economics, the curriculum in statistics consists of diploma, bachelor as also post-graduate courses. However in order to have promising career, it is advisable to complete either the graduate or post-graduate course with specialization.

According to experts, similar to economists, the carrier as statistician is very much promising. Considering the impact of statistical analysis on the future policies of the organization the position of statistician is considered to be very much important and it is one of the highly regarded positions. Normally, statisticians are appointed as consultants. However, some of the organizations and particularly the government would appoint them on a permanent basis or at least on a contractual obligation for certain period of time. Agriculture, industry and banking sector need the assistance of statisticians on a regular basis. It is also said that some of the educational institutions also require statisticians on teaching assignment. Those who have aptitude for teaching can look for these positions.  In fact some of the experienced statisticians even establish their own consultancy services where they even coordinate with experienced economists so that the client would get both the services in one roof.

Why roads at mountains are serpentine?

Why roads at mountains are serpentine?

This is to reduce the effort. It follows the principle of a screw which in turn is a modified form of inclined plane.

See the pic on left. Though we have to do a greater work (against friction) the average force or effort is less and the risk or danger of accident is less.

CBSE 2012

CBSE (Central Board of Secondary Education) has started online counselling for students and parents for Board Exams.

The first phase of this pre-exam counselling will start from Wednesday Feb 1,2012 and will continue until April 16 2012, for those appearing for board examinations this year.

Toll Free Number 1800-180-3456 is allotted to talk with experts. Anyone can call between 8 a.m. to midnight from Feb 1 to April 16, 2012.

This year, approximately 67 experts, including principals, trained counsellors from CBSE affiliated government and private schools and few psychologists are participating in tele-counselling.

Where is electricity stored after it is generated but before it is supplied? (Chat Transcript from FaceBook)

Where is electricity stored after it is generated but before it is supplied?
    • Mahesh Sable Electrical power cannot be stored and,therefore,power plants must produce power as and when demanded.power stations r connected in parallel hence load is equally distributed,electric Power can be adjusted with help of step up or step down transformers.

       

    • Mathew Abraham Transformer does not increase power

       

    • Chitraja Rajan The demand for electricity varies randomly within a day itself…so there should be something which should be adjusted according to the demand.

       

    • Vishnu Mohan G huge capacitors? i think i read somewhere like this.

       

    • Rajat Sharma

      Hi All, the question is very smart, i think electricity stored before generation is stored in Water(DAM), Uranium Rods(Nuclear), HydroCarbons(Coal, GAS). Electricity can only store when it is in Direct Current format like in Batteries, Capacitor(its a very small time to store/release) Well there are many source where we can store electricity. When electricity is in demand then Power generation takes place within huge Alternators, this powers generation takes places in terms of Phase Shift between all the power Houses across the country, if this phase shift is disturb then power grid fails. after this the transformers come into picture so as to reduce Resistance loses.

       

    •  
    • Kannan Kannan Ps in my little knowledge electricity unable to store continuing process of generater get current
      >________________________________

       

    • Chitraja Rajan at the generation side electricity is high ac current ..if it is converted into dc then there should be large containers to store them and also need suitable convertors to convert it in either form every time

       

    • Mathew Abraham In modern generators, there are equipment to control the rate of flow of water and in turn rate of rotation as well as the power generated. SO, it is quite right to say that electricity is generated as and when required. When you switch on a device power generation also increases until it reaches maximum capacity. Thereafter we will get less power. Remember the low voltage we suffer during the evening when the power consumption is maximum a few seconds ago · Like

You can also post your questions and answers and participate in discussions online at http://facebook.com/groups/askphysics/

What Type of questions are asked in Viva Voce?

The methodology of questioning varies from examiner to examiner. The normal way of questioning is to start from the experiment you are alloted.
Example:

What experiment are you doing?
Ans: To determine the value of unknown resistance using metre bridge (Don’t say just metre bridge or unknown resistance alone; you should tell the complete aim of the experiment.)

What is the principle on which the experiment is based?

Ans: The metre bridge experiment is based on the Wheatstone’s Bridge Principle

(You can go on to state the principle; or it will be the next question)

Then the examiner may go on to ask some tricky questions related to Wheatstone’s Bridge.

The questions are generally based on what you answer and usually different sections are asked when you do not give a satisfactory answer.

Have good presence of mind and think before you answer.

You can find some sample questions here arranged experimentwise

A VERY INTERESTING CONVERSATION

A VERY INTERESTING CONVERSATION
Received by email
An Atheist Professor of Philosophy was speaking to his Class on the Problem Science has
with GOD, the ALMIGHTY. He asked one of his New Christian Students to stand and . . .

Professor : You are Christian, aren’t you, son ?
Student : Yes, sir.
Professor : So, you Believe in GOD ?
Student : Absolutely, sir.
Professor : Is GOD Good ?
Student : Sure.
Professor : Is GOD ALL – POWERFUL ?
Student : Yes.
Professor : My Brother died of Cancer even though he Prayed to GOD to Heal him.
Most of us would attempt to help others who are ill.
But GOD didn’t. How is this GOD good then? Hmm?

(Student was silent ) Continue reading “A VERY INTERESTING CONVERSATION”

Time Management – A must follow skill to succeed in Life

We can define time management as the different techniques through which an individual can utilize his time and other associated resources. Moreover, time management brings many benefits for the students such as gaining on time,get motivated and learn to take initiatives, manage to minimize evasion of any sort and much more. You can not get time to review your learning. By time management, you can manage to reduce nervousness.
You are probably here because you want to make the most of your time. You recognize that time is a unique and precious resource that you need in order to do your work and accomplish your goals.
Personal time management skills are essential skills for effective people. People who use these techniques routinely are the highest achievers in all walks of life, from business to sport to public service. If you use these skills well, then you will be able to function exceptionally well, even under intense pressure.
At the heart of time management is an important shift in focus:

Concentrate on results, not on being busy

15 Time Management Tips Continue reading “Time Management – A must follow skill to succeed in Life”

HOW TO PREPARE YOUR ROUTINE TO SCORE GOOD MARKS IN PHYSICS AND SUCCEED IN MEDICAL ENGINEERING ENTRANCE TESTS, IIT (JEE) – PART I

A General Briefing on Studying Physics (for Indian Students)

Quite often we hear “There is no substitute for hard work”

Everyone you come across advise you to work hard.

But,

Mere hard work  will not pay.

 

I know several students who work hard and spent many hours a day in front of books but score pathetic marks / grades.

Why is it so?

What is the problem?

What went wrong?

When we come to Physics, (and in General, Science) reading alone will not help you score big. Whether you read again and again or write the concepts several times, you will not be able to score commendable marks unless you understand the concepts thoroughly and apply the concepts to different situations independently.

Just take the case of “Principle of Conservation of Momentum”

There is no end to the number of questions which can be framed from this single concept.

So, The basic point is understanding concepts  thoroughly.

But How?

Thinking on what you read, hear or see is very important in understanding Physics. When you think, many questions will arise in your mind. Finding the answers to these questions form the basic of understanding the concept.

When you have a question, ask it to your teacher or discuss with your friends.

Remember, A question asked or an idea shared by you may be the beginning of the next scientific revolution

Which Text book?

The NCERT Text book is the one which Indian students should take as the basic one. Not only the +2 level exams and entrance exams but even the Civil Services exams mainly base the core syllabus on the NCERT texts.

The main complaint from the students and some ‘others’’ is that the NCERT  text book is incomplete and donot convey the full idea at several places.

This is intentional. The incompleteness is penned in wisely to enable the students to ask questions and explore beyond the text book.

Telling everything is not the scientific way of learning. There is sufficient scope left in the text book for the students to explore the world they live in and learn themselves.

As the Chinese proverb says,

“Don’t give fish to a hungry man, instead teach him how to fish” (Then he will not be hungry anymore)

Learning to learn is more important than learning itself.

No single text book can tell you everything. No single teacher can tell you everything. A lot is learnt by self through thinking, contemplation, experiment and interrogation.

The NCERT Text Book concentrates on the prescribed syllabus as the core content and give hints, probes and thrusts at places for the readers to go beyond the textbooks and the curriculum.

For scoring good marks in Physics, it is very important master “the  art of problem solving” . Start with solving all the numerical and conceptual problems of the NCERT text book and then go on to solve as much related problems as you can.

Make it a habit to solve 20 – 25 numerical problems related to the topics you learn in Physics daily.

… To be continued.

(Expect soon articles on “managing time”  , preparing for Exams,  “How to Revise” and related items)