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प्रश्न
Answer the following.
How is a shadow formed? Write the conditions required for a shadow to form.
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उत्तर
Whenlightfallsonanopaqueobject, light is obstructed and a dark patch on a screen kept behind is called the shadow. This is because light propagates in a straight line.
If the distance between the object and screen is less, the shadow will be (umbra) dark and smaller.
If the distance is increased shadow will be dim and larger.
Conditions Required for a shadow to form are:
- There should be a source of light.
- An opaque object.
- A screen.
- The opaque object is placed between the source of light and the screen.
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संबंधित प्रश्न
Fill in the blank.
The darkest portion of a shadow is called the ................
State two differences between an umbra and a penumbra.
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?
What is penumbra?
When does a shadow form?
How does the colour of an opaque object affect the colour of the shadow?
What do we need in order to see a shadow?
Sivarajan placed a meter stick in the playground at 7.00 am in the morning. How will the shadow of the stick at noon look in comparison to the one in the morning
What are the properties of 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.
