In the figure shown below, the incident ray and the emergent ray in the respective order are given by:

Correct option is B

Ans. (b) AB and CD

Explanation:

• In the given figure, an incident ray (AB) enters a triangular prism at point B. This is the initial path of light as it moves from air into the prism.
• After passing through the prism, the ray undergoes refraction and emerges from point C as the emergent ray (CD).
• Therefore, AB is the incident ray, and CD is the emergent ray.

Important Key Points:

1. AB represents the incident ray as it enters the prism.
2. CD represents the emergent ray as it exits the prism.
3. Light refracts when entering and exiting the prism due to a change in medium.
4. Refraction at B causes a slight bend in the light’s path as it enters the prism.
5. The emergent ray CD is displaced from the original path A due to the prism's refractive properties.
6. Prisms are often used to analyze refraction and dispersion in light.

Information Booster:

• Incident Ray: The ray of light that strikes a surface, in this case, the side of the prism.
• Emergent Ray: The ray of light that exits from the opposite side of the prism.
• Refraction: The bending of light as it passes from one medium to another, governed by Snell’s law.
• Dispersion: Prisms can also separate white light into its constituent colors, though dispersion is not depicted in this case.