Assertion : The sounds which cannot be heard pleasantly is called noise.
Reason : The sound above 80 dB becomes painful.

Answer

To analyze the given statements, we will break down the assertion and the reason step by step.

### Step 1: Understand the Assertion
- **Assertion**: "The sounds which cannot be heard pleasantly is called noise."
- This statement defines noise as unpleasant sounds. Noise is generally characterized by its disruptive or irritating nature, which can cause discomfort to the listener.

### Step 2: Understand the Reason
- **Reason**: "The sound above 80 dB becomes painful."
- This statement refers to the decibel (dB) scale, which measures sound intensity. Sounds above 80 dB are often considered loud enough to cause discomfort or pain to the human ear.

### Step 3: Analyze the Relationship
- The assertion states that noise is unpleasant, while the reason provides a threshold (80 dB) above which sounds can be painful.
- Sounds that exceed 80 dB can indeed be classified as noise because they are likely to be unpleasant and potentially painful to hear.

### Step 4: Conclusion
- Both the assertion and the reason are true. The assertion correctly defines noise, and the reason accurately describes a characteristic of loud sounds. Therefore, both statements support each other.

### Final Answer
- **Both the assertion and the reason are true.**

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