Question

Energy generation in stars is due to nuclear fusion.
(A) How does nuclear fusion occur?
(B) The energy released in nuclear fission process with Uranium is of the order of _________

Answer 1

In order to answer this question,we must have knowledge about collision of lighter nuclei to form a large one and hydrogen is the lighter nuclei.We should also use the concept of the isotopes of hydrogen.

Complete step by step answer:
(A) Nuclear Fusion is the process in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
Let’s take a look at the conditions necessary to create nuclear fusion in stars and some of the different kinds of fusion that can go on.The core of a star is an intense environment. The pressures are enormous, and the temperatures can be greater than $15{\text{ }}million$ Kelvin. But this is the kind of condition you need for nuclear fusion to take place. Once these conditions are reached in the core of a star, nuclear fusion converts hydrogen atoms into helium atoms through a multi-stage process.
Two hydrogen atoms are merged into a deuterium atom. This deuterium atom can then be merged with another hydrogen to form a light isotope of helium – ${}^3He$. Finally, two of the ${}^3He$ nuclei can be merged to form a${}^4He$atom. This whole reaction is exothermic, and so it releases a tremendous amount of energy in the form of gamma rays.
This fusion cycle is known as the proton-proton chain, and it’s the reaction that happens in stars.

(B) The energy released in nuclear fission process with Uranium is of the order of ${\mathbf{200}}{\text{ }}{\mathbf{MeV}}.$

Note: Sometimes students get confused in nuclear fission and nuclear fusion terms so be kept in the mind that the process in which one heavy nucleus splits into two or more smaller nuclei is known as nuclear fission while the process in which two or more nuclei fuse together to give one heavy nuclei is known as nuclear fusion.