CBSE Class 10 Answered

Differences between nuclear fission and nuclear fusion:

 

1. Fission is the splitting of a large atom into two or more smaller ones and Fusion is the fusing of two or more lighter atoms into a larger one.

 

2. The energy released by fission is a million times greater than that released in chemical reactions, but lower than the energy released by nuclear fusion and the energy released by fusion is three to four times greater than the energy released by fission.

 

3. Fission reaction does not normally occur in nature but fusion occurs in stars, such as the sun.

 

It is possible to carry out the fission reaction in a controlled way and to produce electricity by a controlled chain reaction of nuclear fission of a radioactive substance like U-235 in a set up called the nuclear power plant.

Scientists have been working on controlling nuclear fusion for a long time, trying to make a fusion reactor to produce electricity. So far it has not been ppossible to control the fusion reaction in a contained space as it requires extremely high temperatures and energy released due to this process is also very high. Also, extremely high energy is required to bring two or more protons close enough that nuclear forces overcome their electrostatic repulsion.