You meet a person with prescription glasses of +0.55 dpt.
What is the near point of this person? Express the result as a positive number!
Hint: the near point of a healthy person is 25 cm. An object placed at this distance will form an image at the near point of the person.
use the thin lens formula:
1/f=(1/p) + (1/q)
To find f: 1/f = 0.55dpt
p is 0.25m.
then find q, which is the near point.
To find the near point of a person with prescription glasses, we need to understand how prescription glasses affect the near point.
Prescription glasses correct vision by compensating for the refractive error in a person's eyes. In this case, since the glasses have a prescription of +0.55 dpt, it means that the glasses are designed to correct for farsightedness. Farsightedness is a condition where the eye has difficulty focusing on objects up close.
The prescription strength of +0.55 dpt indicates the amount of lens power required to bring the near point closer to the eye. Positive values indicate farsightedness, so in this case, the glasses are designed to bring the near point closer to the person.
The near point of a healthy person is typically considered to be 25 cm. This means that an object placed at this distance will form a clear image on the retina without any accommodation from the eye. However, for farsighted individuals, the near point is farther away due to the refractive error.
To find the new near point for this person, we can calculate it by adding the prescription strength to the usual near point. In this case:
New near point = Usual near point + Prescription strength
= 25 cm + 0.55 dpt
Now, we need to convert the prescription strength from diopters (dpt) to meters (cm). Remember that the conversion factor is 1 dpt = 100 cm:
Prescription strength in cm = Prescription strength in dpt * 100
= 0.55 * 100
= 55 cm
Therefore, the new near point for this person is:
New near point = 25 cm + 55 cm
= 80 cm
So, the near point for this person is 80 cm.