KVPY 2020-21 SA Exam Previous Papers

Four bulbs : red, green, white and blue (denoted by R, G, W and B respectively) are kept in front of a converging lens (as shown in the figure below). The observer sees that the green and blue bulbs are kept to the left of the principle axis while the red and white bulbs are kept to the right of the principle axis. He also sees that the red and green bulbs are above principle axis while the white and blue bulbs are below the principle axis. The screens ${\mathit{S}}_1$ and ${\mathit{S}}_2$ are set appropriate positions for the focusing to view the images. Choose the figure that correctly represents the images as seen by the observer.