Why don't you get an image for certain object distances ?

Could you get an image on the screen for every object distance with a convex lens ?

To get an image larger than the object one can use

Can you find the minimum limiting object distance for obtaining a real image ? What do you call this minimum limiting object distance ?

We wish to obtain an erect image of an object using a concave mirror of focal length of 15 cm. What should be range of distance of the object from the mirror ? What is the nature of the image ? Is the image larger or smaller than the object ?

Why do you see a diminished image of the arrow ?

Why is the electron in an atom restricted to revolve around the nucleus at certain fixed distances ?

Why don't we drink sea water

If focal length of the concave mirror is 20 cm, we get virtual image if the object placed at a distance……..than 20 cm

Will you get a point image if you place a paper at the focal point ?

How does it possible to get the image at the same distance on the retina ?