When a beam of white light is passed through a prism,violet colour bends the most and red colour the least.

List two causes leading to myopia of the eye. Draw ray diagrams to show the image formation in case of a defective eye and a corrected eye.

$A$ person is unable to read a book clearly when kept at a distance of $25 \,cm$ from his eye. Name the defect. How can it be corrected? Draw ray diagrams for $(i)$ defective eye $(ii)$ corrected eye and explain them.

When red and green light overlap,what color does that region appear?

Why is the blind spot so called?

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