What is Presbyopia?

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?

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.

Cinematography makes use of

$A$ beam of white light falling on a glass prism gets split up into seven colours marked $1$ to $7$ as shown in the diagram. $A$ student makes the following statements about the spectrum observed on the screen.
$(a)$ The colours at position marked $3$ and $5$ are similar to the colour of the core of a hard-boiled egg and the colour of the sky respectively. Is the statement made by the student correct or incorrect? Justify.
$(b)$ Which of the two positions correspond closely to the colour of $(i)$ a solution of potassium permanganate,$(ii)$ danger or stop signal lights?