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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 darkest portion of a shadow is called the ................
Select the correct alternative.
Umbra 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?
State two differences between an umbra and a penumbra.
Draw a ray diagram to show the formation of umbra alone.
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
When does a shadow form?
What are the essential conditions for the formation of shadow?
What are the parts of shadow?
Which of the following can never form a circular 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.
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 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.
