Some laws/processes are given in column-I. Match these with the physical phenomena given in column-II.
`{:(,"Column I",,"Column II"),((A),"Nuclear fusion",(p),"Converts some matter in energy"),((B),"Nuclear fission",(q),"Generally possible for nuclei with low aoimic number".),((C),beta-"decay",(r),"Generally possible for nuclei with high. atomic no".),((D),"Exothermic nuclear reaction",(s),"essentially proceeds by weak nuclear forces".):}`

Answer

To solve the matching question between Column I and Column II, we will analyze each item in Column I and find its corresponding item in Column II based on the descriptions provided.

### Step-by-Step Solution:

1. **Nuclear Fusion (A)**:
- Nuclear fusion is the process where two light atomic nuclei combine to form a heavier nucleus, releasing energy in the process.
- This process generally involves low atomic number nuclei coming together to form a higher atomic number nucleus.
- **Match with (q)**: "Generally possible for nuclei with low atomic number."

2. **Nuclear Fission (B)**:
- Nuclear fission is the splitting of a heavy atomic nucleus into two lighter nuclei, along with the release of energy.
- This process typically occurs with heavy atomic nuclei (high atomic number).
- **Match with (r)**: "Generally possible for nuclei with high atomic number."

3. **Beta Decay (C)**:
- Beta decay is a type of radioactive decay where a beta particle (electron or positron) is emitted from an atomic nucleus.
- This process is governed by weak nuclear forces.
- **Match with (s)**: "Essentially proceeds by weak nuclear forces."

4. **Exothermic Nuclear Reaction (D)**:
- An exothermic nuclear reaction is a reaction that releases energy. Both fusion and fission can be classified as exothermic reactions.
- **Match with (p)**: "Converts some matter into energy."

### Final Matches:
- A - q: Nuclear Fusion matches with "Generally possible for nuclei with low atomic number."
- B - r: Nuclear Fission matches with "Generally possible for nuclei with high atomic number."
- C - s: Beta Decay matches with "Essentially proceeds by weak nuclear forces."
- D - p: Exothermic Nuclear Reaction matches with "Converts some matter into energy."

### Summary of Matches:
- A → q
- B → r
- C → s
- D → p