On passing through a rectangular glass slab, a ray of light suffers one/two/three refractions.

What is the difference between the displacement produced by a rectangular glass slab in a ray of light and the deviation produced by a glass prism?

A narrow beam of white light passes through a triangular glass prism and gets split up into seven colours marked 1 to 7. Which two positions correspond closely to the colour of: 'danger' or 'stop signal lights'?

A narrow beam of white light passes through a triangular glass prism and gets split up into seven colours marked 1 to 7. Which two positions correspond closely to the colour of: potassium permanganate?

A narrow beam of white light passes through a triangular glass prism and gets split up into seven colours marked 1 to 7. A student makes the following statements about the spectrum observed on the screen: " The colours at positions marked 3, 4 and 5 are similar 'to the colour of the sky, leaf and sunflower respectively." Is the above statement made by the student correct or incorrect ? Justify.