Define the term "power of accommodation" of human eye.

What is the range of vision of a normal human eye?

Name the part of our eyes which helps us to focus near and distant objects in quick succession.

Give the scientific names of the following parts of the eye:

(a) carries signals from an eye to the brain.

(b) muscles which change the shape of the eye-lens.

(c) a hole in the middle of the iris.

(d) a clear window at the front of the eye.

(e) changes shape to focus a picture on the retina.

Fill in the following blanks with suitable words:

(a) Most of the refraction of light rays entering the eye occurs at the outer surface of the _______

(b) The part of eye sensitive to light is_______

(c) The part of eye which alters the size of the pupil is_______

(d) When light is dim, the pupil becomes_______

(e) The iris controls the amount of_______entering the eye.

(f) The ciliary muscles control the shape of the _______

(g) To bring light from a distant object to a focus on the retina of the eye, the convex eye-lens needs to be made_______

(h) To bring light from a near object to a focus on the retina of the eye, the convex eye-lens needs to be made_______