AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
A small source of light casting a sharp shadow of an opaque object shows that light travels in straight lines (rectilinear propagation of light).
Source: Chapter 9, Introduction
The examiner expects the key term "straight lines" or "rectilinear propagation." The textbook explicitly states this observation as evidence that light travels in a straight-line path, indicated as a ray of light. One clean sentence is sufficient for 1 mark.