Final answer:
The statement about PD measuring instruments is true: the subject sees a ring of light while the dispenser reads a direct measurement from the eye's scale or a split image of the pupil. Experiments concerning the eye's resolution and response to light illustrate the role of geometric optics in visual perception.
Step-by-step explanation:
Understanding PD Measuring Instruments.The statement describes PD (Pupillary Distance) measuring instruments used in optometry. The subject sees a ring of light around a central dot inside the instrument. Meanwhile, the dispenser sees the subject's eye with a scale for direct measurement. It is true that some instruments provide a split image of the pupil to help in measuring PD. Regarding the resolution of the eye, a take-home experiment was described where one would measure the diameter of the pupil under different lighting conditions. Pupils dilate in the dark and constrict in bright light. This experiment illustrates the eye's ability to adjust to varying light intensities. Another experiment involves drawing two lines and observing them from various distances to understand the pupil's resolution capability, in relation to geometric optics. In a different context, the bright spot focused on paper using converging lenses is indeed an image of the Sun. All these concepts are essential in understanding how light and optics are integral to the functionality of not only instruments but also the human eye.