The atomic bomb uses the principle of `………………` .

Answer

**Step-by-Step Solution:**

1. **Understanding the Atomic Bomb**: The atomic bomb is a weapon that releases a massive amount of energy through nuclear reactions.

2. **Principle of Nuclear Fission**: The atomic bomb operates on the principle of nuclear fission. This process involves the splitting of heavy atomic nuclei into smaller, lighter nuclei.

3. **Role of Neutrons**: In the case of the atomic bomb, a heavy nucleus such as uranium is bombarded with neutrons. When a neutron collides with the uranium nucleus, it can cause the nucleus to become unstable and split apart.

4. **Energy Release**: The fission of the uranium nucleus releases a significant amount of energy, as well as additional neutrons. This energy is released in the form of heat and radiation.

5. **Chain Reaction**: The neutrons released from the fission can then go on to collide with other uranium nuclei, causing them to undergo fission as well. This leads to a chain reaction, where each fission event produces more neutrons, which in turn cause more fission events.

6. **Exponential Growth of Reactions**: As the chain reaction continues, the number of fissions increases exponentially, leading to an enormous release of energy in a very short time, which is the explosive power of the atomic bomb.

7. **Conclusion**: Therefore, the atomic bomb uses the principle of nuclear fission to achieve its destructive capability.

**Final Answer**: The atomic bomb uses the principle of **nuclear fission**.

---