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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 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
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 and penumbra both. Label the parts umbra and penumbra in your diagram.
State the conditions when only the penumbra of an opaque object is obtained on the screen.
Tick the correct answer.
Umbra is a region of
What is penumbra?
When does a shadow form?
What are the properties of shadow?
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
| O W S | A K E | O P A Q | U E O | B J E T | T S M |
| S H A D |
______ is always against, opposite side of light source.
The lighter shade of shadow is the ______.
Which of the following can never form a circular shadow?
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 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.
