A nuclear reaction in which two light nuclei merge to form a heavy
nucleus with release of energy is called fusion reaction.

As the bindin energy per nucleon of a heavy nucleus is much more than
the bindin energy per nucleon for the two combinin light nuclei.Hence,
when two lighter nuclei combine to form a heavy nucleus(havin mass
number A<50) with a realease of energy is called fusion reaction.

When two protons and two neutrons combine to form a helium nucleus,then
about 28Mev energy is released.

Durin fusion reaction,some mass is lost and its equivalent energy is

given out.

It is difficult to produce to fusion reaction. Two postively charged
light nuclei must be brought very close to one another.To do so work
work has to be done against the electrostatic forces of repulsion
between the positively charged nuclei.Thus,a large amount of energy
is required to produce fusion reaction.

Let us now take the example of fusion reaction when two deutrons are
combined to form helium nucleus,24Mev energy is released during this
process.

2^H + 2^H.........4^He + 24Mev

But there is very little chance of formation of 4^He nucleus by the
combination of two duetrons.The probabily of finding such a reaction
is great where one proton or one neutron is produced.

DIFFERENT METHODS FOR PRODUCING FUSION REACTION:-

1.Accelerator:-
One method used is to provide the nuclei with very high velocity by
an accelerator.But this method of nuclear fusion cannot be used
on a large scale.
2.Increase of Temperature.
It is based upon the principle that the speed of atoms of substance
increases with the increase of temperature of that substance. To
start a fusion reaction the temperature at which the required speed
of the lighter nuclei,can be achieved is about 10 million degrees
celcius.At such very high temperature the reaction that teakes place
is called THERMO NUCLEAR REACTION.
Generally such a high temperature can not be obtained.However,during
the explosion of an atom this temperature can be achieved for a
very short time.
Until now the fusion reaction is takin place only in hydrogen bomb.In
this case very high temperature is obtained during the explosion of an
atom bomb,due to this temperature the fusion reaction between 2^H and
3^H starts.In this way large amount of energy is released with the
explosion.

Fusion Reaction In The Sun:-

The sun is composed of hydrogen.It has a little amount of helium and a
and a slight amount of other heavy elements.
A large amount of energy keeps issuing out of it continuously at all
times.The temperature of its core is about 5 million degrees celcius.
Its energy is due to fusion reaction called p-p reaction.During this
process two hydrogen nuclei or two protons combime to form deutron.

Since the fusion reaction is free from radioactive products,so it ll be
safe,exempted from pollution.

Fusion reaction has not been yet brought under control thus it cannot be used
for electricity.

Learn more about this author, Talhah Masood Khan.
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