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प्रश्न
Select the correct alternative.
Penumbra is a region of
पर्याय
complete darkness
complete brightness
partial brightness
none of the above
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उत्तर
partial brightness
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संबंधित प्रश्न
Fill in the blank.
The darkest portion of a shadow is called the ................
Fill in the blank.
The less dark portion of a shadow is called the .................
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?
State two differences between an umbra and a penumbra.
In the following diagram, draw rays to form umbra on the screen.
State the conditions when only the penumbra of an opaque object is obtained on the screen.
Why is it that the birds flying in the sky do not cast their shadow on the earth?
What are the essential conditions for the formation of shadow?
What do we need in order to see a shadow?
______ is always against, opposite side of light source.
The ______ is the darkest part of a shadow.
The lighter shade of shadow is the ______.
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?
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.
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.
