We saw that, image formed by convex lens is
Position of the object | Position of the image | Relative size of the image | Nature of the image |
At infinity | At focus F 2 | Highly diminished, point-sized | Real and inverted |
Beyond 2F 1 | Between F 2 and 2F 2 | Diminished | Real and inverted |
At 2F 1 | At 2F 2 | Same Size | Real and inverted |
Between F 1 and 2F 1 | Beyond 2F 2 | Enlarged | Real and inverted |
At focus F 1 | At infinity |
Infinitely large or
highly enlarged |
Real and inverted |
Between focus F 1 and optical Center O | On the same side of the lens as the object | Enlarged | Virtual and erect |
Now, let us see where convex lens is used
Convex lens is used as
- It is used as Magnifying Glass
- It is used to Make Microscope
- It is used in spectacles to correct the vision. It cures defects called hypermetropia (far sightedness) where patients can't see objects closer to them
Uses of Concave Lens
We saw that, image formed by concave lens is
Position of the object | Position of the image | Relative size of the image | Nature of the image |
At infinity | At focus F 1 | Highly diminished, Point - Sized | Virtual and erect |
Between infinity and optical centre O of the lens | Between focus F 1 and optical centre O | Diminished | Virtual and erect |
Now, let us see where concave lens is used
Concave lens is used as
- It is used as a spy hole in doors (where we can see visitor from a small opening)
- It is used in spectacles to correct the vision. It cures defects called myopia (near sightedness) where patients can't see objects far away
- They are used in camera to focus on a single object, Hence we get a clearer picture
- It is used in Flashlights. Concave lenses are used in flashlights to widen the beam produced by the bulb.