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प्रश्न
Select the correct alternative.
Penumbra is a region of
विकल्प
complete darkness
complete brightness
partial brightness
none of the above
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उत्तर
partial brightness
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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 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?
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.
Why is it that the birds flying in the sky do not cast their shadow on the earth?
Tick the correct answer.
Umbra is a region of
What is penumbra?
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 ______.
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.
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 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.
