Question

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. 

(i) The colours at positions marked 3 and 5 are similar to the colour of the sky and the colour of gold metal respectively. Is the above statement made by the student correct or incorrect? Justify. 

(ii) Which two positions correspond closely to the colour of 

(a) brinjal, 

(b) ‘danger’ or stop signal lights? zzz

Answer 1

(i) The statement made by the student is incorrect. Positions marked 3 (yellow) and 5 (blue) are similar to the colour of gold metal and the colour of the sky respectively. The student is stating the nature of colours in reverse order. 

(ii) (a) The position marked 7 (violet) corresponds closely to the colour of a brinjal. 

(b) The position marked 1 (red) corresponds closely to the colour of ‘danger’ or stop signal lights.