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प्रश्न
State two differences between an umbra and a penumbra.
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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.
Umbra is a region of
Select the correct alternative.
Penumbra is a region of
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 and penumbra both. Label the parts umbra and penumbra in your diagram.
In the following diagram, draw rays to form umbra on the screen.
In the following diagram, draw rays to form a penumbra on the screen.
State the conditions when only the penumbra of an opaque object is obtained on the screen.
Tick the correct answer.
Umbra is a region of
Answer the following.
How is a shadow formed? Write the conditions required for a shadow to form.
What is shadow?
When does a shadow form?
What are the essential conditions for the formation of shadow?
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
| O W S | A K E | O P A Q | U E O | B J E T | T S M |
| S H A D |
Three torches A, B and C shown in the following figure are switched on one by one. The light from which of the torches will not form a shadow of the ball on the screen.
A torch is placed at two different positions A and B, one by one, as shown in the following figure.
The shape of the shadow obtained in two positions is shown in the following figure.
Match the position of the torch and shape of the shadow of the ball.
Three identical towels of red, blue and green colour are hanging on a clothes line in the sun. What would be the colour of shadows of these towels?
A football match is being played at night in a stadium with flood lights ON. You can see the shadow of a football kept at the ground but cannot see its shadow when it is kicked high in the air. Explain.
