Given,
Focal length (f) of the concave mirror = -10 cm
Case-1
The image is real, and its magnification (m) is -2.
Using the magnification formula, we get
Now, using the mirror formula, we get
Case-2
The image is virtual and has a magnification 'm' of 2.
Using the magnification formula, we get
v=-2u
Now, using the mirror formula, we get
Thus, the object should be placed at a distance of 5 cm in front of the concave mirror.