A: Ray optics assumes that light travels in a straight line which is disapproved by diffraction effects, yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments.
R: Typical sizes of apertures involved in ordinary optical instruments are much larger than the wavelength of light.

Options

A. IF both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark(2)
C. IF Assertion is true statement but Reason is false then mark(3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To analyze the assertion and reason provided in the question, we can break down the statements and evaluate their truthfulness and relationship.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Ray optics assumes that light travels in a straight line which is disapproved by diffraction effects."
- In ray optics, light is treated as rays that travel in straight lines. This assumption works well for many optical instruments. However, diffraction, which occurs when light encounters obstacles or openings comparable in size to its wavelength, demonstrates that light can bend and spread out, contradicting the straight-line assumption.

2. **Evaluating the Assertion**:
- The assertion is **true** because ray optics does assume straight-line propagation of light, and diffraction effects indeed show that this assumption can be incorrect under certain conditions.

3. **Understanding the Reason (R)**:
- The reason states that "Typical sizes of apertures involved in ordinary optical instruments are much larger than the wavelength of light."
- In typical optical instruments, such as cameras and microscopes, the apertures (like lenses and openings) are generally much larger than the wavelength of visible light (approximately 400-700 nm). This means that diffraction effects are minimal, allowing the ray optics approximation to be valid.

4. **Evaluating the Reason**:
- The reason is also **true** because the size of the apertures being larger than the wavelength of light means that the effects of diffraction are negligible in most practical situations.

5. **Relationship Between Assertion and Reason**:
- While both the assertion and reason are true, the reason does not provide a correct explanation for the assertion. The assertion discusses the limitations of ray optics due to diffraction, while the reason explains why ray optics can still be effectively used in practice despite those limitations.

6. **Conclusion**:
- Therefore, the correct answer to the question is: Both assertion and reason are true, but the reason is not the correct explanation for the assertion.

### Final Answer:
- Both assertion and reason are true, but the reason is not the correct explanation for the assertion.