Two nuclei are fused together by raising the temperature. What can we infer about this process?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → It is called thermonuclear fusion.
Option (1) It is not possible to achieve this. — Incorrect. At a high enough temperature, the nuclei move fast enough to overcome their Coulomb repulsion and fuse. This is how the interior of the stars produces energy.
Option (2) It is called thermostatic fusion. — Incorrect. There is no fusion process of this name. The word “thermostatic” refers to keeping a temperature steady.
Option (3) It is called thermonuclear fusion. — Correct. Raising the temperature gives the nuclei enough kinetic energy to overcome the Coulomb barrier. So they come within the range of the nuclear force and fuse. Fusion achieved in this way is called thermonuclear fusion.
Option (4) The kinetic energy provided will always be insufficient to cause fusion. — Incorrect. Fusion goes on in the sun even though its interior is at about \( 1.5\times10^{7}\,\mathrm{K} \), because many protons there have energies much above the average.
NCERT (2026-27):
Nuclear Fusion – Energy Generation in Stars – “When fusion is achieved by raising the temperature of the system so that particles have enough kinetic energy to overcome the coulomb repulsive behaviour, it is called thermonuclear fusion.”