Question

The focal length of a concave mirror is 20cm. At what distances from the mirror an object must be placed to produced. (I) a real image (ii) a virtual image (iii) both three times the size of the object.

Answer 1

(I) To produce a real image,the object must not be placed between P and F. i.e.,u>20cm
(II)To produce a virtual image,the object must be placed btw focus and P.i.e.,u <20cm