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प्रश्न
State the conditions when only the penumbra of an opaque object is obtained on the screen.
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उत्तर
If the size of the source of light is bigger than the size of the opaque object, the size of the umbra is very small. If the screen is moved away from the object, the umbra vanishes and only the penumbra remains.
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संबंधित प्रश्न
Fill in the blank.
The less dark portion of a shadow is called the .................
Select the correct alternative.
Umbra is a region of
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?
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.
Why is it that the birds flying in the sky do not cast their shadow on the earth?
What is shadow?
What is penumbra?
When does a shadow form?
What are the essential conditions for the formation of shadow?
What is a shadow? What things are necessary for the formation of a shadow?
______ is always against, opposite side of light source.
The lighter shade of shadow is the ______.
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.
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.
