Accommodation means the adjustment of light going into the eye for image formation.

$A$ person needs a lens of power $-4.5\, D$ for the correction of her vision.
$(a)$ What kind of defect in vision is she suffering from?
$(b)$ What is the focal length of the corrective lens?
$(c)$ What is the nature of the corrective lens?

With the help of scattering of light,explain the reason for the difference in colours of the Sun as it appears during sunrise/sunset and noon.

For which position of the object does a convex lens form a virtual and erect image? Explain with the help of a ray diagram.

$(i)$ Write the range of distance for a person having normal vision.
$(ii)$ $A$ person needs to use glasses for reading a newspaper. Identify the defect in his vision and the type of lens he would need to correct it.
$(iii)$ Sometimes when we enter into a dark room from bright sunlight,we are unable to see objects clearly. Why?

Describe an experiment to discuss the recombination of dispersed light.