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.

• Take a thick sheet of cardboard and make a small hole or narrow slit in its middle. • Allow sunlight to fall on the narrow slit. This gives a narrow beam of white light. • Now, take a glass prism and allow the light from the slit to fall on one of its faces as shown in Fig. • Turn the prism slowly until the light that comes out of it appears on a nearby screen. What do you observe? You will find a beautiful band of colours.