Question

The limit of resolution of the eye is approximately
(A) ${1^o}$
(B) 1’
(C) 1 mm
(D) 1 cm

Answer 1

Hint: To find the limit of resolution of the human eye, we need to be clear about the definition of resolution of the eye and on what factors resolution of eyes is dependent. The visibility of the human eye is limited up to a distance. This concept will be a great help in answering the question.

Complete step by step answer: The eye is an optical instrument that has a small aperture called a pupil which controls the amount of light that enters our eyes. Resolution of the eye is dependent on the pupil size which would imply that our eyes could resolve more detail in the dark when the pupil is large than in bright light when it is small.
The human eye's natural pupil size is 2 mm, which determines the minimum angular resolution of the eye and enables us to see tiny objects as close as possible to our eyes, although there is a minimum distance of about 25 cm for comfortable vision. But the number quoted is 0.1 mm for the smallest resolvable dimension, indicating that the diffraction limit is a key factor in the strength of visual resolution.
We can also write it as the human eye has an angular resolution of about 1 arcminute (0.02 degrees or 0.0003 radians) which enables us to distinguish things that are 30 centimetres apart at a distance of 1 kilometer.
Hence, option (B) is correct option.

Note: Due to the limit of resolution "One of the stars that you see might actually be two stars that are separated by a really tiny angle," says Allanach. "You wouldn't be able to resolve them, they would just look like one star."