[填空题]
(a) How far from a 50.0-mm-focal-length lens musgr,k(2 cci qtcb,h9 -rijj44 lcap8- lt an object be placew,-v az d0h3axto3m.. tetl: ld if its image is to be magnified 2.00h.t3 a-lx azwed:0.3 omt vl,t× and be real? mm
(b) What if the image is to be virtual and magnified 2.00×? mm
