Class 12

Biology

Cell: Structure and Functions

Nuclei

Calculate and compare the energy released by (a) Fusion of 1.0 kg of hydrogen deep within Sun (b) The fission of 1.0 kg of $_{235}U$ in a fission reactor

Amount of hydrogen, $m=1kg=1000g$

1 mole, i.e.e , 1 g of hydrogen $(_{1}H)$ contains $6.023×10_{23}$ atoms. Therefore 1000 g of hydrogen contains $6.023×10_{23}×1000$ atoms.

Within the Sun, four $_{1}H$ nuclei combine and form one $_{2}He$ nucleus. In this process $26MeV$ of energy is released. Hence the energy released from fusion of $1kg$ $_{1}H$ is

$E_{1}=46.023×10_{23}26×10_{3} =39.149×10_{26}MeV$

B:

Amount of $_{92}U$= 1 kg = 1000 g

One mole i.e. 235 g of $_{92}U$ contains $6.023×10_{23}$ atoms. Therefore 1000 g of $_{92}U$ contains $2356.023×10_{23}×1000 $ atoms.

It is known that the amount of energy released in the fission of one atom of $_{92}$ is $200MeV$

Hence, energy released from the fission of 1 kg of $_{92}$ is

$E_{2}=2356.023×10_{23}×1000×200 =5.106×10_{26}MeV$

$E_{2}E_{1} =7.67≈8$

Therefore, the energy released in the fusion of 1 kg of hydrogen is nearly 8 times the energy released in the fission of one kg of uranium.