Question

Nuclear fusion has not yet been harnessed as an energy source because

Answer 1

B

Step-by-step explanation:

Energy is hard to control.

Answer 2

Before getting an answer for it first we have to understand nuclear fusion.

Nuclear fusion is a thermo-nuclear reaction in which two light unstable nuclei will form a heavy stable nuclei. In this process there will be some mass defect which will be converted into energy as per Einstein's mass energy equivalence theorem.

The theorem is stated as
`E = mc^(2)` where c is the velocity of light and m is the mass converted into energy.

One take an example of fusion in sun where 4 hydrogen atoms combine to form a helium nucleus which are explained below-

`H_(1)^(1)+H_(1) ^(1) =H_(1) ^(2) +e_(+1) ^(0) +energy`

`H_(1) ^(2) +H_(1) ^(1) =He_(2) ^(3) +energy`

`He_(2) ^(3)+H_(1) ^(1) =He_(2) ^(4) +e_(+1) ^(0) +energy`

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`4H_(1) ^(1) = He_(2) ^(4) +2e_(+1) ^(0) +energy`

Here
`e_(+1) ^(0)` is the positron.

In this process very high temperature is needed which is approximately equal to the temperature of the sun i.e
`10^(6) K`

Such temperature is very difficult to initiate the reaction on the earth surface. It should be carried out in an sustainable way also .Otherwise It will cause nuclear hazards.