R = Radius of curvature of mirror = – 20 cm
Case–I:
Given u = - 40 cm, v = ?
Using mirror formula
Negative sign of v indicates image formed is real at a distance of 13.33 cm from the mirror.
Negative sign of m indicates inverted image |m|<1 the image formed is diminished. Also
The positive sign of v indicates virtual image. The image is 40 cm behind the mirror. Also
The positive sign of m indicates erect image. Also |m|>1 the image formed is enlarged. Also
