Shadows and Penumbra

• Shadows are produced because light travels in straight lines
• A larger image is produced from a point source, due to diverging light rays from the single bulb
• Using the projecting lamp, which has a bulb at its focus and so gives a collimated beam, the shadow produced is similar in size to the object

Shadows, umbra and penumbra. Shadows are formed when an object blocks the path of light. The shadow is the space behind the object where no light falls. Shadows have a shape similar to that of the object that produces them. We can get two types of shadows. A completely shaded area is known as umbra, whereas a partially shaded area is called penumbra.

A clear, distinct shadow is formed when the light source is smaller than the object so that all of the light is blocked.

• Inclined plane, with 3 different trackterminals — 5491.11
• Projector with 12V 20W halogen lamp — 4414.18
• Slider for projector — 4417.17
• Slider for holder — 4417.01
• White metal screen — 4418.35

• Why does the single bulb produce a larger shadow?
• Why does the projecting lamp produce a shadow similar in size to the object?
• Why is the shadow the same shape as the object?
• What is a solar eclipse?