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Photoelectric effect

 

I wanted to to know that why the attraction of electrons towards the positive plate of the the CRT is not taken into account in the Einstein’s explanation of the photoelectric effect and only the velocity imparted by the striking photon is considered.

 

English: German-born theoretical physicist Alb...

Thanks!

 

Regards
Amit Singh
XII-B

Answer:

I request you to kindly read the story well. Every aspect is dealt in detail. Please go thoroughly through the text material or the link to photoelectric effect provided in this page.

 

 

Usage of energy in nuclear fission and fusion

I read in a biographic book about Albert Einstein that the energy produced from burning materials is much less than the energy stored in them (the authored suggested the book itself as an example – he wrote that it can power a ship for about 100 years).
I would like to know how much of the energy of a material is used in nuclear fission and fusion.

Asked Avishag

Answer:

Nuclear explosion
Nuclear Explosion (Source: WIkiPedia)

Energy obtained by burning a substance is meagre compared to the energy contained in it. According to Einstein’s mass energy relation (E=mc2), the energy released by converting 1 gram of any substance completely into energy = 0.001 (mass) x 300,000,000 x 3,00,000,000 (square of velocity of light).

But, in nuclear reactions, the entire mass is not converted into energy. The tremendous energy liberated during a nuclear explosion is the result of a small portion of the mass of nucleus undergoing the reaction getting converted into energy.

For example, when a uranium 235 atom undergoes nuclear fission the enrgy liberated is 200 MeV = 200 x 1.6 x 10 -19 J

In 235 g of U-235 there are 6 x 1023 atoms.

So if that much of U-235 atoms undergo fission, the energy liberated will be about 1,00,00,000 J.

Hope that you might have had an idea of it.

on Einsteins research

Albert Einstein

if the papers of Einstein depend upon speed of light as its base, and the particles which have speed greater than the light could pose treat to be it. then in that case why cant that particle could be set as the Einsteins theorms base so that it doesnt violate and simple corrections could correct the theorms!!

(Sajin Asks)

Cosmological Constant and its Significance

Abdul Najeeb asked via Facebook:

Would you plz explain me what is a cosmological constant? When Einstein snubbed it as the "biggest blunder" in his life, what else is the real importance of the constant? Also what is cosmological acceleration and its’ effect on the constant…plz…but in simple words…plzzzz:)))))

Ans:

The cosmological constant was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe.

image image

Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory on the idea that the universe is unchanging.However, the discovery of cosmic acceleration in the 1990s has renewed interest in a cosmological constant.

{courtesy : Wikipedia}

More details will be added soon

Nature of light, relativity and blackholes

Prasanna asked:

we know light has got dual nature. & blackholes has got enormous gravity from which even light cant escape. how can gravity can influence a mass less stream of particles like gravity?

Ans:

Do you know why solar eclipse is watched with great importance by the scientific community?

OK

Einstein’s theory of General Relativity was proved right(?) when bending of light by masses was observed in reality.

Please go through the links below and hope that you’ll find an answer there.

http://en.wikipedia.org/wiki/General_relativity

http://www.suite101.com/

Matter, Antimatter and Einstein’s equation

It is my understanding that when antimatter comes in contact with matter that there is nothing left but pure energy.

And since energy and matter are interchangeable (E=Mc2) doesn’t that mean you are actually left with all matter and no antimatter?

Asked Ken

Answer:

The equation E = mc2 tells about mass – energy relation and both matter and antimatter has a positive mass.

Mass Energy conversion and the Big Bang

Ajesh Asked:

Respected sir, in the famous theory of Albert Einstein which is of mass energy equivalence  he stated a formula E = mc2 .
sir does this mean that mass can be converted in to energy or the opposite will happen .
it is even stated in the big bang theory  that the universe was created with respect to the  above theory is that so?

 

Answer:

The mass energy conversion and the equivalence is a widely discussed topic in relation to the creation of the universe or the Big Bang.

There is some energy missing in calculation when we consider the equivalence; this is called dark energy.

Please read the following links for more details.

http://csep10.phys.utk.edu/astr162/lect/cosmology/hotbb.html

http://www.big-bang-theory.com/

http://ssscott.tripod.com/BigBang.html

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