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प्रश्न
A torch is placed at two different positions A and B, one by one, as shown in Fig. 11.9.
The shape of the shadow obtained in two positions is shown in Fig. 11.10
Match the position of the torch and shape of the shadow of the ball.
उत्तर
A → a; B → b
As the position of torch changes, we can observe the change in shape of shadow.
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संबंधित प्रश्न
Fill in the blank.
The darkest portion of a shadow is called the ................
Fill in the blank.
The less dark portion of a shadow is called the .................
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.
Draw a ray diagram to show the formation of umbra and penumbra both. Label the parts umbra and penumbra in your diagram.
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
Answer the following.
How is a shadow formed? Write the conditions required for a shadow to form.
What is shadow?
How does the colour of an opaque object affect the colour of the shadow?
What do we need in order to see a shadow?
What is a shadow? What things are necessary for the formation of a 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.
Three torches A, B, and C shown in Fig. 11.7 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?
Three identical towels of red, blue and green colour are hanging on a clothes line in the sun. What would be the colour of shadows of these towels?
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.
