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प्रश्न
State two differences between an umbra and a penumbra.
उत्तर
Umbra
- It is the portion of shadow where no light reaches from the source of light due to the opaque object.
- It is completely dark.
Penumbra
It is the portion of shadow where a portion of light from the source of light reaches the shadow even in the presence of the opaque object in between them.
It is not completely dark but is dim (or less bright).
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संबंधित प्रश्न
Select the correct alternative.
Penumbra is a region of
What is a shadow? Give a reason for its formation.
Draw a ray diagram to show the formation of the shadow of an opaque object by a point source of light. How is the size of shadow affected if the screen is moved away from the object?
Draw a ray diagram to show the formation of umbra alone.
In the following diagram, draw rays to form a penumbra on the screen.
What is penumbra?
When does a shadow form?
What are the essential conditions for the formation of shadow?
What do we need in order to see a shadow?
What are the parts of shadow?
The ______ is the darkest part of a shadow.
The lighter shade of shadow is the ______.
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Correct the following statements.
- The color of the shadow of an object depends on the color of the object.
- Transparent objects allow light to pass through them partially.
A torch is placed at two different positions A and B, one by one, as shown in Fig. 11.9.
The shape of the shadow obtained in two positions is shown in Fig. 11.10
Match the position of the torch and shape of the shadow of the ball.
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A student had a ball, a screen and a torch in working condition. He tried to form a shadow of the ball on the screen by placing them at different positions. Sometimes the shadow was not obtained. Explain.
