What is the complementary color of blue?

What is the cornea?

At noon,the sun appears white because:

Name the colours of the visible spectrum.

Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

$(i)$ 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?