Question

Name two natural phenomena based on the property that light travels in straight lines.

Answer 1

The phenomenon of light traveling along a straight line path is called rectilinear propagation of light.

The two natural phenomena based on the rectilinear propagation of light are as follows:

1. Lunar Eclipse: As we know that Earth revolves around Sun and the moon revolves around Earth. When Earth is positioned such that Sun, Earth, and Moon are aligned in a straight line, then the shadow of Earth falls on the moon and the moon does not appear from Earth. This is caused due to rectilinear propagation light because the sunlight travels in straight lines and falls on Earth. Thus, the shadow of Earth falls on the moon. This phenomenon is called a lunar eclipse.
2. Solar Eclipse: While revolving around the sun, when the moon comes in between the sun and Earth, then the shadow of the moon falls on the Earth. Hence, the sun is partially visible from Earth as the moon in between the sun and Earth. This is caused due to rectilinear propagation of light. The phenomenon is called a solar eclipse.