If a spherical mirror has a radius of curvature of .24 m and and object is placed in front of it and magnified to twice its size: is the mirror concave, convex, or either? And what is the object's distance? I determined that the mirror was concave, because the question said that the image was twice the object's size and convex mirrors decrease image size. Is this correct? I'm having trouble finding the object's distance too. I know that M = - di/do. And M will either = 2 or -2 because the image could be real or virtual. From the question I got that R = .24 and since F = R/2, F = .12 Then, using the equation 1/do + 1/di = 1/F, I rearranged to get do + di = F and since F = .12, do = .12 - di I solved for di using M = - di/do with M = 2, so 2 = - di/do rearraged to, di = - 2do Plugging this to the spherical-mirror equation gave me: do = .12 - (- 2do) Solving gives: do = - .12 m Is this correct? Am I going about this the right way, or am I way off base? Any help is appreciated. Thank you.