- A 1 meter tall object was placed 10 meter in front of a normal eye. The size of the image on the retina will be (consider distance between lens and retina = 1.7 cms)
(1) 0.17 mm (2) 1.7 mm
(3) 3.4 mm (4) 170 µm
Explanation:
The magnification of the image formed by the eye’s lens is the ratio of the image height to object height and equals the negative ratio of the image distance to the object distance. Given the distance between the lens and retina and the position of the object, the retinal image size can be derived simply by the product of object size and magnification.
Calculation:
hi=ho×vu
In this example,
hi=1×0.01710=0.0017 m=1.7 mm
Summary Table
Parameter Value Object height ho 1 m Object distance u 10 m Image distance v 1.7 cm (0.017 m) Image size hi 1.7 mm
Conclusion:
The image size on the retina for a 1-meter tall object placed 10 meters away from a normal eye with a lens-retina distance of 1.7 cm will be approximately 1.7 mm.
Answer: (2) 1.7 mm
