The image of an extended object, positioned perpendicular to the principal axis of a mirror, will be erect if

Step-by-step solution

The lateral magnification for a spherical or plane mirror is given by m = - v u . For an erect image, the magnification m must be positive, which means m > 0 . - v u > 0 v u This implies that the object distance u and the image distance v must have opposite signs. According to the Cartesian sign convention, a real object has u 0 . Similarly, a real image has v 0 . Since u and v must have opposite signs, there are two valid conditions. First condition: u 0 (virtual image). Second condition: u > 0 (virtual object) an