Final answer:
The image of an object placed 25 cm from the eye forms 27.5 cm behind the retina.
Step-by-step explanation:
To determine how far in front or behind the retina the image of an object placed 25 cm from the eye forms, we need to consider the lens-to-retina distance, which is given as 2.5 cm.
The formula to calculate the image distance is:
1/f = 1/v - 1/u
Where f is the focal length of the eye lens, v is the image distance, and u is the object distance.
In this case, the near point is 100 cm, so the focal length (f) can be calculated as:
1/f = 1/100 - 1/Infinity
Since the cornea to retina distance is 2.5 cm, the image distance (v) can be calculated as:
v = u - 2.5
Substituting the values, we have:
1/100 - 1/Infinity = 1/v - 1/25
Simplifying the equation, we find that the image distance (v) is 27.5 cm.
Therefore, the image of the object is formed 27.5 cm behind the retina.