## Found on the net – Physics Catalyst

We browse the internet to find out useful website for the learners. One such website we found today

http://physicscatalyst.com/chapter.php

You can download study materials, attempt tests online, download E-Books and many more. Make a visit now!

## Significance of Infinity

Significance of Infinity in Physics and Life
RKDas (MSc- Physics, Banaras Hindu University, India)

Goal:

The author is trying to prove the existence of infinity and infinite energy in the entire universe. By doing so, he raises some basic questions against the profoundly established concepts of prevalent physics.

Introduction to Infinity
In Sanskrit, infinity is termed as ananta, which is something without any limit or end. It is synonymous with Sanskrit term puurna, the full and complete. There is a phonetically similar term apeiron in Greek that stands for potentially unlimited or indefinite.
A specific beauty of the concept of puurna is such that ‘even if a puurna is subtracted or taken out of the puurna, the remainder is but an unreduced puurna itself (puurnasya puurnam aadaaya puurnam eva avashishyate).’ Following the same ideology, a practical statement may be made: the infinity is a one single entity, if there are many infinities, where is the room for placing more than one such infinity? Possibility of multiple infinities defies the basic requirements of infinity, which is not finite or limited.

Review of Zero and Infinity
Zero is a number. The zero, just as a number does exist in reality. It is such a small number or the smallest possible quantity that it is equal to nothing. Zero is an imaginary concept. In reality, ‘zero content’ does not exist; the zero is a no entity; the zero is without a true existence. There is no true zero. Zero is like a pure untruth.
Zero is a greatly useful tool for arithmetic operations. Continue reading “Significance of Infinity”

## How was your AISSCE CBSE Class 12 Physics Exam 2013?

How was the CBSE Class 12 Physics Exam today?

Was it easy or difficult?

Many students reported that the questions were unexpected and extra ordinarily tough. What was your experience?

Were there questions beyond your comprehension?

Were there questions out of Syllabus?

Post your responses Now!

Anju R  writes:

Hi,
The Physics CBSE exam was tough.It was not beyond the syllabus but it was confusing and was asked in a twisted manner.Almost all the students who prepared for the exams didnot leave any derivations,laws etc.But the saddest part was that they asked the big derivation for just one mark and only very few were asked.And most questions were unexpected ones.
It was painful when I saw that after the exam almost all the students were crying.Sitting for a whole night for studying the derivations,laws etc.. gave nothing to us other than tears.We were happy after the English exam but the Physics exam gave a terror over us about Board Exams.I think 90 %  of the students could not complete saying that it was a lengthy paper.

During the exam I could see many sitting with great confusion while few others in a hurry to complete  it and the rest of them sitting sadly.By the grace of God I completed 5 minutes before the alloted time and didn’t leave any question.I hope CBSE will consider us.

Yours sincerely,
Anju.R

## Faster than Light!

Mathew Abraham (A Physics Teacher in KVS) claims (on FaceBook) that faster than light communication and transfer of matter is possible and the fact will be revealed in near future.

See the transcript below.

I believe and maintain that “faster than light communication and transfer of matter is possible”. We have to find how?

• Vishnu V Mohan Maybe communication.But wat abt matter?
• Mathew Abraham It’s somewhat like a revelation to me, I hope that particles travelling faster than light would soon be discovered and that discovery would lead to interstellar travel in near future

## Physics Musings on Beer

Do you know there are a lot of Physics facts hidden behind a glass of beer.

Institute of Physics (UK) has launched a Christmas website based on beer, to help explain some of the more peculiar scientific phenomena hidden in a glass of beer.

http://www.physics.org/cheersphysics/

The site explains many facts of Physics too based on the beer story.

It says that the bubbles are not rising but they are constantly falling in a g;ass of beer. Can’t believe? Visit the site to know more.

## Class 12 physics question bank

Download an excellent collection of questions with answers for CBSE Class 12 Physics

## Question Bank in Physics Class XII

The collection will also be helpful for students of other syllabuses.

The file consists of syllabus, key points, collection of very short Answer (1 mark), Short answer type question – solved (2 marks), short answers (3 marks), Long answers (5 marks), Solved numericals and 3 sample papers.

The contents are arranged chapter-wise. Any student will find this a boon for easy preparation and to score better marks in Physics.

## Alternating Current and Direct Current

AC/DC (electricity)

Electricity is the most widely used form on energy because it is most efficiently distributed and transported. Also it can be easily converted to other forms of energy like mechanical energy, heat energy etc. Also since it is one of the fastest forms of usable energy it is used in logic digital circuits for computation since it gives the fastest results. It is this versatility of electricity that makes it so useful for modern life.
Of course electrical energy has various forms as well. It can be stored charge, alternating current or direct current. Each of these forms of energy have different advantages. Now we know that most  of power that we get in our homes is in the form of AC. However it is not necessarily the most used form of energy. In fact most electronic equipment use DC power and converts AC from the supply to DC. Then why is it made AC in the first place. Let us discuss that shall we?

Continue reading “Alternating Current and Direct Current”

## Inside a Car Engine

(Internal Combustion Engine)

We cannot imagine modern life without the car. The automobile has been one of the singular most amazing inventions of the 21st century and almost defines modern times. Inside of most mechanical petroleum based vehicles is the internal combustion engine.
Today we shall have a brief look at the internal combustion engine and it’s basic working principles.
Basically the the internal combustion engine is a cyclic machine that works on the basis of polytropic expansion laws.
polywhat?!

Ok so a polytropic process is one in which the gas equations work differently than that stated in boyle’s law because temperatures need to be constant for the famous law to work. (Pressure*Volume= constant at constant temperature)
Here since during expansion of the gases the temperature does not remain constant and hence the law looks like:
Pressure*Volumex =constant

The variable x depends upon the gas used.

So as you can see pressure will have to change greatly for the equivalent volume to change and to keep the equation valid. That’s exactly what happens in an internal combustion engine where an small explosion changes the pressure greatly but the limited volume is not much and hence the equivalent change in volume remains small.

First cycle: Suction
As you can see from the diagram the camshaft being slightly oval is rotating about a central point which for a certain time pushes the lever which opens the valve connecting the gasoline tank to the combustion chamber. The engine is so tuned such that when the fuel flows from the gasoline tank to the combustion chamber the bigger rotating structure downwards pulls the piston downwards. Hence the fuel gets trapped in the chamber when the valve closes.

Second cycle:Compression
This is the part where things get interesting. With the fuel trapped inside the chamber due to valve action the wheel rotates such that it pushes the piston above and compresses the fuel. This fuel now now has to withstand high pressure as the piston has lowered the volume greatly. When it is compressed at the maximum a spark plus in the chamber is ignited which causes a small explosion to increase pressure rapidly and push the piston downwards.[remember the part where i told you that the volume is quite limited but the change in pressure is enormous]

Third cycle: Expansion
Here work is obtained from the engine as it causes the rotation in the rotating part attached to the piston to increase. The expansion is the part where the actual energy is obtained from the engine. The wheel continues to rotate by inertia. This is why sometime you need to move the car a bit before getting it to work. It is because the first two parts of the cycle need energy to function and it’s the third cycle which actually provides work.

Fourth cycle: Exhaust
Now the second camshaft is made to rotate at such a speed that by the end of the third cycle  the exhaust valve opens up and the fumes that remain after the explosion is forced out by the upward movement of the piston.
Now the second cycle starts where the piston is made to move by inertia and hence the cycle continues.

That’s it! That’s how the internal combustion engine works. Now obviously you will not get an exact replica of this engine inside your car. Rather they have as many as four piston moving up and down to form a 4-stroke internal combustion engine. Also they have a variety of cooling mechanisms and noise filters to reduce the noise from the explosion that takes place inside the machine. However this is the absolute basic and all other made upon this model. There are differences between a petrol and a diesel engine but then again they are not much different from this model.
So now the looking up the car engine  won’t seem like an engineering job at NASA anymore, would it?!

## Hydrogen Economy

As the world’s fossil fuels are continuously depleted with increasing use we run the risk of facing a shortage soon enough in the future.  Alternatives are a must as we already face the heat here in India with capping of LPG cylinders. One of the biggest consumers of fossil fuels are petroleum-based vehicles. Whether it is a diesel car or a petrol car or a CNG vehicle it doesn’t really matter. They all use fossil fuels which are bound to run out one day or the other. We need to continuously improve current efficiencies of transportation vehicles while still improving on alternative energy sources. One of the biggest solutions to alternative energy solutions are using hydrogen instead of carbon based fuel as an energy source.

Hydrogen as a fuel has a lot of potential to be used as energy because it not only releases a large amount of energy when burnt but it also prevents the release of toxic fumes as pollutants.

Let’s do a little bit of math shall we?

I promise it won’t be too large.

Bond energies of hydrogen

The bond energy of the hydrogen bond is 103 kcal/mole. And the bond energy of the hydrogen oxygen bond is 110 kcal/mole. Also the oxygen molecule has 116 kcal/mole of energy.

Therefore the energy released on formation of the water molecule requires breaking one oxygen molecule and two hydrogen molecules first.

That would mean the energy required = 2 x 103 + 116 = 322 kcal/mole

But when water is formed the energy released is = 4 x 110 = 440 kcal/mole

Hence the net energy gain = 440 – 322 = 118 kcal/mole

And this simple math shows the huge amount of energy which is gained on burning hydrogen as a fuel. If a human being were to be powered up by a hydrogen engine he would run 52 miles on just 1 litre! Hydrogen based cars can theoretically provide mileage as good as 93 miles per gallon which is still much better than gasoline based cars providing 35 miles per gallon.

Yes and that’s exactly why hydrogen is a potential energy alternative.

This picture shows exactly what the components of the hydrogen economy consist of.I won’t talk about all the boring points in detail but only some of the parts which are really interesting.

Production and delivery

Hydrogen has a huge source in the form of our vast oceans and seas which provide an ample source of hydrogen. The problem is converting the water to hydrogen which requires energy in the first place.

Well right now they use natural gas and other petroleum products as well as biogas to produce hydrogen. Yes production is actually the biggest hurdle to the hydrogen economy. Hydrogen requires huge amounts of energy to be produced.(It only makes sense since it produces a huge amount of energy on combustion as well.) People are actively working on getting hydrogen to be obtained from a safe source. There are many technologies like aluminium based production (still waiting to be patented) for effective hydrogen production.

And yes there are several hoaxes doing the rounds around the internet which claim to have made super efficient methods to obtain hydrogen from water and hence make cars that run miles on just plain water!!! Well NASA itself has yet to make such a breakthrough but of course there is no giving up hope as people are still trying.

Although I am optimistic that this  can be effectively taken care of using solar , wind , hydel power and various other renewable energy sources(like i told you before the future depends on all energy renewables working together) Then the hydrogen can be transported using storage tanks to fuel stations where the vehicles can refill their tanks!

And no I am not talking about science fiction. This is reality as industries work to implement these systems into the current economy.

Fuel cells

This is the talk of the town when it comes to hydrogen based economy. Fuel cells use a continuous supply of hydrogen to be directly converted to energy using a chemical reaction. This means efficiencies are quite high when using a fuel cell to power up a vehicle as compared to using internal combustion engines to power up a car.

There is huge money in the R&D for fuel cells in the automobile sector.There have been lots of hydrogen based fuel cells which are running commercially as well. Although there has been electric vehicles which have been shown to have much higher efficiencies they lack the power or speed pick up of fuel cell based cars and car maniacs out there swear by top speeds and revving pick up.

Storage

Now this is a real tricky issue hydrogen is the lightest of all elements out there and it is easily the least dense of all gases. In fact 1 gram of hydrogen would occupy as much as 22.4 litres! that too at 0 degrees celsius. Not too good when considering that we would need more than that to provide decent mileage to the vehicles. Well scientists have been looking for ways to combat this dilemma.

One of the ways include in-situ production of hydrogen.

It means the hydrogen would not be carried directly as a fuel. Instead hydrogen containing compounds would be used to generate the hydrogen at the time of running the car. However this method reduces efficiency significantly and renders the use of the vehicle as useless!

Another one of the methods include storage of hydrogen in a really efficient way

This means nanotechnology again! Yes the use of carbon nanotubes to store hydrogen has been deemed a potentially powerful method to store huge quantities of hydrogen in the vehicles. That however is a costly method and current research includes making hydrogen storage even cheaper.

Safety?

Now this is a bit of a tricky issue because hydrogen is even more susceptible to combustion than petroleum. Although that also means that fires breaking out won’t produce toxic fumes but then again they will bring out a bigger bang if they accidentally catch fire. Also current hydrogen storage techniques are not exactly 100% leak proof which means the dangers of accidents are higher! However this can be offset by using standards and protocols to enhance the safety factor of using hydrogen.

So what’s the real problem in implementation of hydrogen as a potential energy source?

Well this again lies in costs. Changing equipment and technology that has been built on petroleum will cost huge amounts and also current petroleum-based vehicles and fuel rates are cheaper than those of hydrogen based ones. Of course this should rapidly change in the very close future. In fact there are many companies already that provide hydrogen cars and hydrogen refuelling outlets.

Yes these are real hydrogen cars in the market out there.