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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
What is a shadow? Give a reason for its formation.
Draw a ray diagram to show the formation of umbra alone.
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 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
What is shadow?
What is penumbra?
When does a shadow form?
What do we need in order to see a shadow?
Sivarajan placed a meter stick in the playground at 7.00 am in the morning. How will the shadow of the stick at noon look in comparison to the one in the morning
The ______ is the darkest part of a shadow.
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.
Correct the following statements.
- The colour of the shadow of an object depends on its colour of the object.
- Transparent objects allow light to pass through them partially.
On a sunny day, does a bird or an aeroplane flying high in the sky cast its shadow on the ground? Under what circumstances can we see their shadow on the ground?
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 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.
