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How is electricity made from water and coal?

Tazim asked: “How is electricity produced from coal and water?”


The question is whether

  • “How is electricity produced from water and how is electricity produced from water?
  • or
  • How is electricity produced from coal and water TOGETHER?

Electricity can be produced from water using hydel (hydroelectric) power stations.

Water is also used in almost all power stations like thermal and nuclear where the heat produced is used to boil water to convert it into steamwhich is then used to rotate turbines to produce electricity.

The upper reservoir (Llyn Stwlan) and dam of t...

Coal is often used as a fuel in thermoelectric power statiuons. the heat obtained by the burning of coal is used to boil water and to produce staem. the steam at high pressure is then utilized to rotate turbines and thus to produce lectricity in generators.

Download excellent questionbank and worksheets in Physics for class X

Mr. MS Kumaraswamy, a trained graduate teacher in Kendriya Vidyalaya Donimalai has prepared an excellent set of question banks and worksheets in Physics and maths for classes VI to X.\You can doenload the Physics question bank at the following Link.


Click here to download excellent questionbank and worksheets in Physics for class X 


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Can animals be left or right handed?

Human beings are either left handed or left handed. Is it true with other animals too? Are some animals left handed and the others right handed?
The kind of work done by animals are different from that by human beings,
The animals do not use their limbs as HANDS as we do.
However, the research done on apes shows that they may be righthanded or left handed.
The home grown pets which behave different from naturally growing animals, show preference of left over right or right over left. A study on the cat family showed that they prefer left PAW  to the right.
As far as human beings are concerned, righthandedness is one HABIT developed through training. By nature ee may use both hands equally, and may prefer a particular hand for a given kind of activity.

Critical thinking – An essential trait for excellence in competitive exams

Nowadays, the number of students asking genuine doubts are found decreasing day by day. the main reason behind this is the lack of critical thinking. Think deeply on things you learn, hear and see. find answers to the questions arising in your mind. If you develop the habit of critical thinking, it is certainly help you to excel in exams. As we discussed earlier, “Questioning every answer is more important than answering every question”

How to develop critical thinking?

An easy way to develop the habit of critical thinking is by solving puzzles – Sudoku, crossword puzzles, tiles rearrangement, chess and the like. Try solving the logical reasoning type questions, picture based puzzles and reasoning ability tests etc. asked in various competitive exams.

The logical reasoning tests are helpful not only to excel in cometitive exams, but it will help you in moul;ding your personality also.

I personally advice reading all the works on Sherloke holmes by sir arthur Conan Doyale. the way sherloke holmes comes to various copnclusions will certainly inspoire us in being a keen observer and a critical thinker and more over a great problem solver.

Exchange – The essence of Existence

Most of the forces of nature are caused by some sort of exchange of particles among the bodies – as the scientists explain them. Otehrwise, they didn’t have an explanation to the ‘Why” behind the forces. Why shouold a body exert a force on another body at a distance? How does the body know that there is a body kept at a distance and then exert a force on it? On eof the theories explaining the cause is that the forces are of an exchange type. H Yukawa used this concept to explain the origin of nuclear forces. The force between the constituents of the nucleus is called nuclear force. This is believed to be the strongest force in nature. But this is of very short range. This force can be experienced only at a distance of the order of 10-15 m. Yukawa said that tehre are some tiny particles called mesons which are exchanged between the nucleons and that this exchange process is responsible for holding the nucleons together inside the nucleus. He compared the exchange process to two doge fighting each other for a bone. as long as there is the bonme. the two dogs will be BOUND fighting for the bone. Each of the two dogs wants to possess the bone, but they are trying to snatch the bone from the other. If one is taking it, the other will continue to fight to get back and thus the bond between them is maintained during the process of snatching the bone from others.

We have a lesson of life to learn from here. any relation is based on some sort of exchange or the other. there may be exchange of love, gifts, money etc. The exchanging binds the minds.

The famous words “Don’t ask what the country has given to you, but ask yourselves what you have given to the coubtry” is relevant here.

We are born with many talents and capabilities. have we identified what we are worth? Are we utilizing the talents possessed by us for the betterment of humankind? Ask yourselves. If your answer is no, then this ius the time. Think how betsyour talents can be put to for the betterment of your coubtry, state or city. “We are the people” is one of the stories I remember now. When we say the citizens of a country (say, our country) we often think about ourselves but include all others except ourselves to the group of citizens and criticicze them. Let the change start from you. when you improve yourselves, there is atleast one good citizen who loves the country and ready to fully utilize the talents and potentials. Seeeing your work the others will also follow suite. Be the change that you want to see!

How does methane gas affect the ozone layer?

Why methane gas is lighter than air and how does it affect the ozone layer?

(Asked Shreyanka, Class VII C, KV Bidar)

Answer: The density, i.e; the mass per unit volume of methane is less than that of air (which is a mixture of many gases) Methane react with ozone converting it into oxygen and thus the ultraviolet absorbing power is lost. More percentage of UV rays will reach the earth. Normally about 50% of the UV rays reaching the upper atmosphere are absorbed or reflected back.

Read more here

  1. http://en.wikipedia.org/wiki/Methane
  2. http://ozone.unep.org/pdf/qa.pdf

Example for Inertia of rest

When you try to pull out a sheet from a note book, a slow motion raises the entire book, But a sudden motion detaches the sheet. See the video below for a demonstration.

The paper get detached because of the inertia of rest of the book.

What is inertia of rest?

The inherent property of a body at rest to resist any change in its state of rest is called inertia of rest.

OR in simple terms,

The incapability of a body to change its state of rest by itself is caled inertia of rest.

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