Define dispersion of white light.

$A$ person is advised to wear spectacles with concave lenses. What type of defect of vision is he suffering from?

$A$ person can see distant sign boards clearly but cannot read clearly a book which is at $25\, cm$ from his eye. Giving reason,identify the defect. Draw a labelled ray diagram to illustrate this defect and its correction.

Identify the correct statement regarding the propagation of light of different colours of white light in air.

When white light is incident on a yellow pigment,which color of light is not reflected?

When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?