What is the time difference between the actual sunset and the apparent sunset?

Which color is produced by mixing blue and red?

The figure below shows a glass prism placed in the minimum deviation position. $A$ ray of monochromatic light is incident on its face $AB$. Copy the diagram and show the refracted and the emergent ray. Mark the angle of deviation. State any two factors on which the angle of deviation depends.

How is long-sightedness corrected?

What is the difference in the colours of the Sun observed during sunrise/sunset and at noon? Provide an explanation for each.

Dispersion of white light occurs because every colour travels with a different speed in a transparent medium.