Question

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

Answer 1

Answer:

B

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-

                                                      $H_{1}^{1}+H_{1} ^{1} =H_{1} ^{2} +e_{+1} ^{0} +energy$

                                                      $H_{1} ^{2} +H_{1} ^{1} =He_{2} ^{3} +energy$

                                                      $He_{2} ^{3}+H_{1} ^{1} =He_{2} ^{4} +e_{+1} ^{0} +energy$

                                                       -----------------------------------------------------------------------

                                                        $4H_{1} ^{1} = He_{2} ^{4} +2e_{+1} ^{0} +energy$

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.