Problem 15 - A Complete Resource Book in Chemistry for JEE Main

Question

Fusion bomb involves (a) explosion of TNT (b) combustion of oxygen (c) destruction of heavy nucleus into smaller nuclei (d) combination of lighter nuclei into bigger nucleus

Step-by-Step Solution

Answer

(d) Combination of lighter nuclei into a bigger nucleus

Step 1: Identify the Key Concept

Understand that the exercise is asking about the nature of a fusion bomb. The fusion bomb operates on the principle of nuclear fusion, which involves nuclear reactions that combine lighter atomic nuclei to form a heavier nucleus.

Step 2: Analyze Each Option

Examine what each option implies: (a) Exploding TNT involves chemical reactions and is unrelated to nuclear processes. (b) Combustion of oxygen also involves chemical oxidation reactions and not nuclear reactions. (c) Destruction of heavy nucleus refers to nuclear fission, not fusion. (d) Combination of lighter nuclei into a bigger nucleus is the process of nuclear fusion.

Step 3: Determine the Correct Option

Based on the analysis, identify that option (d) Combination of lighter nuclei into a bigger nucleus, describes the principle of nuclear fusion which is what powers a fusion bomb.

Key Concepts

Nuclear Reactions

Nuclear reactions are processes that change the structure of an atomic nucleus. Unlike chemical reactions which involve electrons and their configurations, nuclear reactions happen between the nuclei of atoms. These reactions usually release or absorb a significant amount of energy due to the interactions between particles within the nucleus.
There are two main types of nuclear reactions:

• Fission: The splitting of a heavy nucleus into two or more smaller nuclei, accompanied by the release of energy.
• Fusion: The merging of two light atomic nuclei into a heavier nucleus, releasing energy in the process.

Fusion is particularly interesting since it powers the sun and other stars. It is a source of immense energy, much more than fission, because the binding energy per nucleon is higher in lighter nuclei than in heavier ones. Therefore, when lighter nuclei fuse, they release significant amounts of energy.

Fusion Bomb

A fusion bomb, also known as a hydrogen bomb, utilizes the power of nuclear fusion. It is one of the most powerful types of nuclear weapons and relies on the principle of fusing lighter atomic nuclei into a heavier one. This release of energy is intensely higher than in fission bombs.
Unlike atomic bombs that purely use fission, fusion bombs start a reaction with fission just to create the extreme temperatures and pressures needed for fusion to occur. This process is called thermonuclear fusion and it contributes to the massive explosion associated with hydrogen bombs. The key points to remember about fusion bombs are:

• Fusion reactions occurring inside release significantly more energy than fission reactions.
• They require extremely high temperatures and pressures, conditions similar to those in the sun.
• This bomb design overcomes the limitations of fission, allowing for an exponentially more powerful explosion.

Atomic Nuclei

The atomic nucleus is the very small and dense region at the center of an atom, composed of protons and neutrons. It accounts for nearly all the mass of an atom.
Nuclei are held together by the strong nuclear force, one of the four fundamental forces of nature. This force is considerably stronger than the electromagnetic force that tries to push protons apart inside the nucleus, owing to their like charges. The characteristics of atomic nuclei that are central to understanding nuclear reactions include:

• Binding Energy: The energy required to disassemble the nucleus into its constituent protons and neutrons. Higher binding energies per nucleon imply more stable nuclei.
• Stability: The ratio of neutrons to protons affects nuclear stability. Isotopes with too many neutrons or protons can be radioactive.
• Isotopes: Atoms with the same number of protons but different numbers of neutrons. Some isotopes are unstable and lead to radioactive decay.

Understanding these aspects helps clarify why energy is released in both fission and fusion processes.