# The linear magnification of a concave mirror can be positive or negative. Why?

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The linear magnification of a concave mirror can be positive or negative. Why?

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The linear magnification of a concave mirror is m =(h_(2))/(h_(1))= "size of image"/"size of object" = v/u
Clearly, m gt 1, when image is enlarged, and mlt1, when image is smaller in size than the object. Further, when image is inverted and real, h_(2) is negative, h_(1) is positive. Therefore, m is negative, when image is erect and virtual, h_(2) is positive, h_(1) is positive. Therefore, m is positive..