Rectilinear Propagation & Pin-hole Camera

Rectilinear Propagation of Light

Light travels in straight lines, a phenomenon known as rectilinear propagation. This principle helps explain the formation of shadows and eclipses.

Shadows and Eclipses

• Shadows: Formed when an object blocks light, creating a dark area behind it.
• Eclipses: Occur when one celestial body moves into the shadow of another. For example, a solar eclipse happens when the Moon blocks sunlight from reaching Earth.

The Pin-hole Camera

A pin-hole camera is a simple camera without a lens, using a tiny hole to project an inverted image onto a screen inside the camera.

How It Works

• Light from an object passes through the pin-hole.
• The light forms an inverted image on the opposite side of the camera.

The image is inverted because light travels in straight lines, crossing over at the pin-hole.

Image Formation

The size of the image depends on the distance between the pin-hole and the screen, as well as the distance from the object to the pin-hole.