Final answer:
A nearsighted person with a far point of 80 cm requires a concave lens with a power of -1.25 diopters to correct their vision. This lens, also known as a diverging lens, will adjust the person's focal point to enable clear distance vision.
Step-by-step explanation:
A nearsighted person who has a far point of 80 cm will need a diverging lens, or a concave lens, as a corrective lens because a nearsighted person cannot focus on objects that are far away. The purpose of the diverging lens is to adjust the focal point in such a way that it coincides with the person's far point, enabling them to see distant objects clearly. To calculate the power of the corrective lens, you can use the formula P = -1/f, where P is the power in diopters and f is the focal length in meters.
For a nearsighted person with a far point of 80 cm (0.8 m), the lens formula gives us:
P = -1/f = -1/0.8 = -1.25 D
Therefore, the power of the contact lens needed to correct this person's vision to standard vision is -1.25 diopters.