Question

The diagram shows a triangular prism used for tracing the path of ray AB due to the refraction through the prism. Observe the diagram and answer the following:

1. State the correct eye position from the points P, Q, R and S to see the images of the points A and B in the same line through the prism.
2. If the ray, after entering the prism, suffers total internal reflection, then which would be the appropriate position out of P, Q, R, and S to see the image due to TIR?

Answer 1

1. Place the eye at R, in the direction of the emergent ray. The ray emerging from the prism is deviated towards its base.
2. Place the eye at S, in the direction in which the ray emerges after total internal reflection. The ray path inside the prism is reflected at the surface before emerging, so its exit direction is different from that in (a).