Explain the phenomenon of rainbow formation in the sky. Draw the labelled ray diagram in support of your explanation.
Dispersion of white light and the rainbow
High importanceUsually 2 marks a paper · mostly assertion-reason and very short answers · asked in 3 of the last papers
Notes are being written
The board questions below are real and complete — they come from the CBSE papers themselves. The written notes for this topic are still being prepared.
Board questions on this topic
3 from the CBSE papers we hold — the exact wording the board used.
Assertion (A): The rainbow is a natural spectrum of sunlight in the sky. Reason (R): Rainbow is formed in the sky when the sun is overhead and water droplets are also present in air. Select the correct answer from codes:
- (a) Both A and R are true and R is the correct explanation of A.
- (b) Both A and R are true, but R is not the correct explanation of A.
- (c) A is true, but R is false.
- (d) A is false, but R is true.
A narrow beam XY of white light is passing through a glass prism ABC as shown in the diagram. Trace it on your answer sheet and show the path of the emergent beam as observed on the screen PQ. Name the phenomenon observed and state its cause. [Diagram shows a triangular glass prism ABC with incident beam XY entering face AB at point Y, and a screen PQ placed to the right of the prism.]
