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प्रश्न
What is a shadow? Give a reason for its formation.
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उत्तर
When light falls on an opaque object, light is obstructed and a dark patch on a screen kept behind is called a shadow. This is because light propagates in 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.
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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
State two differences between an umbra and a penumbra.
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.
Tick the correct answer.
Umbra is a region of
Answer the following.
How is a shadow formed? Write the conditions required for a shadow to form.
What is penumbra?
How does the colour of an opaque object affect the colour of the shadow?
What are the properties of shadow?
______ is always against, opposite side of light source.
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.
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.
