What do you understand by persistence of image?

Explanation

**Step-by-Step Solution:**

1. **Definition of Persistence of Image**: The persistence of image refers to the phenomenon where an image remains on the retina of the eye for a brief period after the object has moved or changed. This means that the image does not disappear immediately when the object is no longer in view.

2. **Example of a Ceiling Fan**: When a ceiling fan is at rest, we can see each blade clearly. However, when the fan is in motion, the blades appear to blur together, and we perceive them as a continuous circle rather than distinct blades. This is due to the persistence of image effect, where the image of the blades remains on the retina for a short time even after they have moved.

3. **Illustrative Example with a Cardboard**: Another example can be illustrated using a cardboard with drawings. If you draw a cage and a parrot on one side of the cardboard and then rotate it quickly, the images will blend together due to the persistence of image. The eye retains the image of the parrot and cage for a fraction of a second, creating the illusion of motion.

...