Question

Where should an object be placed in front of a concave mirror to as to obtain its :
a) inverted and diminished image, and

b) inverted an enlarged image ?​

Answer 1

Answer:

Explanation:

In short, when an object is kept outside the centre of curvature (C) i.e. in between infinity and centre of curvature, the image formed is real, inverted and dimished and in between C and F (focus).

Answer 2

Explanation:

As given (for a concave mirror)

               mAmB=1 ,

or            mA=1/mB ,

It is clear from the above relation that 

        if mA>1 

  then  mB<1       (condition:both are not equal to 1) ,

 it means we get a diminished image in  position  B. As we know that diminished and inverted image is obtained, when the object's position is beyond C for a concave mirror. Hence, position  B is beyond C.

Now, as  mAmB=1, it means both mA and mB have same sign. But for the position of B, beyond C, mB is -ive (because, image is inverted), therefore other position  mA  is also -ive.

As  mA>1 and -ive, it means image is inverted and enlarged, which we get in the position between F and C for a concave mirror

Hope this helps you out