Why can you not use a concave mirror as a rear-view mirror in vehicles?

A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12cm and its sharp image is formed at a distance of 24cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?

With the help of a labelled diagram explain how a convex lens converges a beam of parallel light rays.

What is the difference between a real image and a virtual image? Give one example of each type of image.

Which of the following diagrams shows the ray of light refracted correctly?

A concave mirror produces three times magnified real image of an object placed at 10 cm in front of it. Where is the image located?

Describe the nature of image formed when the object is placed at a distance of 20cm from a concave mirror of focal length 10cm.

Which lens would you prefer to use while reading small letters from a dictionary?

‘‘A concave mirror of focal length 15cm can form a magnified erect as well as inverted image of an object placed in front of it.’’ Justify this statement stating the position of the object with respect to the pole of the mirror in both cases for obtaining the images.