Give Scientific Reasons:
1. A simple microscope is used for watch repairs.
  1. When an object is placed within the focal length of a simple microscope (convex lens), its magnified and erect image is obtained on the same side of the lens.
  2. By adjusting the distance between the object and the lens, the image can be obtained at the least distance of distinct vision.
  3. Thus, a watch repair can see minute parts of a watch more clearly with the head of a simple microscope.
  4. Hence, simple microscope is used for watch repairs
2 Marks
2. One can sense colours only in bright light.
  1. The retina of our eye is made up of many light sensitive cells. The rod shaped cells respond to the intensity of light while the cone shaped cells respond to various colours.
  2. The cone shaped cells do not respond to dim light and function only in bright light.
  3. Hence, we can sense colour only in bright light.
2 Marks
3. We cannot clearly see an object kept at a distance less than 25 cm from the eye.
  1. When we try to see nearby objects, the eye lens bulges and its focal length decreases.
  2. However, there is a limit to which the focal length of an eye lens can decrease. The focal length of the eye lens cannot be decreased beyond certain limit.
  3. Therefore, we cannot see an object kept at a distance less than 25 cm from the eye as it puts strain on the eye.
2 Marks
  Home

This page was last modified on
30 July 2019 at 03:18

⇈