I clear  II sharp  III poor IV dark Which of the above happens when the hole of a pinhole camera is diminished?

Analysis of the Question

This question tests your understanding of the principles of a pinhole camera. Specifically, it asks how the quality of the image formed changes when the size of the aperture (the hole) is reduced (diminished).

Concept Explanation

A pinhole camera works on the principle of the rectilinear propagation of light (light travels in straight lines).

1. Image Sharpness: When the hole is small, light rays from each point of the object pass through the hole to form a distinct point on the screen. As you make the hole smaller, the overlap of light rays from different parts of the object decreases, making the image sharper.
2. Image Brightness: The hole acts as the "window" for light to enter the camera. If the hole is made very small, less light enters the camera. Consequently, the image becomes dimmer (less bright).
3. The Trade-off: There is a balance in pinhole camera design. If the hole is too large, the image is bright but blurry. If the hole is too small, the image is sharp but very dark (dim).

Step-by-Step Solution

• Effect of diminishing the hole: • I (Clear): As the hole gets smaller, the image becomes clearer (sharper) because the rays are more focused. This is correct. • II (Sharp): This is synonymous with "clear" in this context. The image becomes sharper as the aperture size decreases. This is correct. • III (Poor): This would happen if the hole were made larger, causing the image to become blurred. This is incorrect. • IV (Dark): As the hole gets smaller, less light enters, making the image darker. While this is a physical consequence, in the context of standard JAMB physics questions regarding image quality (clarity), the focus is usually on the improvement of the image definition (I and II).

Looking at the options provided, the combination that describes the improvement in image quality due to a smaller hole is I and II.

Conclusion

When the hole of a pinhole camera is diminished, the image becomes clearer and sharper. Therefore, I and II are the correct descriptions of the image quality.

Exam Tip: Always remember the "Pinhole Rule": Smaller hole = Sharper image but Dimmer image; Larger hole = Brighter image but Blurry image.