Activity 11.4 Let us explore (Page 158) Table 11.2 Observation of shadows Class 7
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Activity 11.4 Let us explore (Page 158) Class 7
Table 11.2 Observation of shadows Class 7
| Action | Observations regarding shadow |
| 1 The screen is removed. | |
| 2. The object is removed. | |
| 3. The torch is switched off. | |
| 4. The object is moved closer to the screen, keeping the torch and the screen fixed. | |
| 5. The object is moved closer to the torch, keeping the torch and the screen fixed. | |
| 6. The object is tilted, keeping the torch and the scree® fixed. | |
| 7. The colour of the object is changed. |
Answer:
| Action | Observations regarding shadow |
| 1. The screen is removed. | No shadow visible, as there’s no surface for it to form on |
| 2. The object is removed. | No shadow is formed because of no opaque. |
| 3. The torch is switched off. | No shadow, shadow forms in light. |
| 4. The object is moved closer to the screen, keeping the torch and the screen fixed. | Shadow becomes sharper and smaller. |
| 5. The object is moved closer to the torch, keeping the torch and the screen fixed. | Shadow becomes larger and blurrier. |
| 6. The object is tilted, keeping the torch and the scree® fixed. | The shape of the shadow changes according to the tilt of the object. |
| 7. The colour of the object is changed. | No, shadow remain in the same colour (dark). |
Conclusions:
We need a source of light, an opaque object, and a screen to observe a shadow. The colour of the shadow remain same i.e., dark, even the object is of any colour.
(i) When the opaque object was a shiny object like a polished steel plate, I got a shadow on the screen, but I also saw that there was a bright spot of light on the wall on the opposite side. Why was it so? Class 7
Answer:
A bright spot of light on the wall on the opposite side was because polished steel plate changed the direction of light. The change in direction of the light by a mirror or polished surface is called the reflection of light.