Q 7. We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.
For the image to be erect it has to be virtual and therefore as per convention v has to be positive
v > 0
u < 0
f < 0
fu > 0
u - f > 0
u > f
Therefore the object must be placed between the pole and the focus of the mirror.
i.e -15 cm < u < 0
The image formed would be virtual and larger than the object.