Assertion: To observe diffraction of light the size of obstacle/aperture should be of the order of `10^-7m`.
Reason: `10^-7m` is the order of wavelength of visible light.

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "To observe diffraction of light, the size of the obstacle/aperture should be of the order of \(10^{-7} m\)."

**Explanation**:
Diffraction is a phenomenon that occurs when light waves encounter an obstacle or aperture that is comparable in size to their wavelength.

### Step 2: Understand the Reason
The reason given is " \(10^{-7} m\) is the order of wavelength of visible light."

**Explanation**:
The wavelength of visible light typically ranges from about \(400 nm\) to \(700 nm\), which is equivalent to \(4 \times 10^{-7} m\) to \(7 \times 10^{-7} m\). Thus, \(10^{-7} m\) is indeed a suitable approximation for the wavelength of visible light.

### Step 3: Analyze the Relationship
Since diffraction occurs when the size of the obstacle or aperture is comparable to the wavelength of light, and given that \(10^{-7} m\) is the order of the wavelength of visible light, the assertion is correct.

### Step 4: Conclusion
Both the assertion and the reason are correct, and the reason correctly explains the assertion.

Thus, the final conclusion is:
- **Assertion**: True
- **Reason**: True
- **Explanation**: The reason correctly explains why the assertion is true.

### Final Answer
Both the assertion and the reason are correct, and the reason is the correct explanation of the assertion.

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