Question

Write down the difference between :- ( 2 marks)

Umbra and Penumbra​

Answer 1

Explanation:

This is the required answer of this question

Answer 2

Answer:

Shadows form when light shines upon an object. While this is a simple concept, the shadow volume behind the object can reveal startling phenomena. For example, a lunar eclipse occurs only when the moon is full and when it passes through part of the Earth’s shadow. Physicists describe shadow volume in terms of umbra and penumbra.

Explanation:

The Umbra

In physics, the umbra refers to the darkest part of the shadow. If you aim a light source directly at an object, the blackest portion of the shadow directly behind the object is the umbra of the shadow. In astronomy, if the sun is shining directly on the western hemisphere of the earth, the eastern hemisphere is bathed in darkness, and objects behind the earth (such as the moon or other planets) are in the earth’s umbra.

The Penumbra

Penumbra refers to the lighter shading that hangs on the outskirts of the umbra. The penumbra is not a true shadow. The Lighting Design and Simulation Knowledgebase describes the penumbra as a gradient: The shading gradually lessens from shadow to light as the penumbra stretches away from the umbra.