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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.
Penumbra is a region of
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?
Tick the correct answer.
Umbra is a region of
What is shadow?
What is penumbra?
How does the colour of an opaque object affect the colour of the 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 ______.
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 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.
