If the distance between object and its two times magnified virtual image produced by a curved mirror is 15 cm, the focal length of the mirror must be :
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If the distance between object and its two times magnified virtual image produced by a curved mirror is 15 cm, the focal length of the mirror must be :

G1 Physics · Accepted Answer

Image v = 15 – u m = 2 = –v/u 2 = –(15 – u)/(–u) 2u = 15 – u 3u = 15 ⇒ u = 5 cm v = 15 – u = 15 – 5 = 10 cm 1/f = 1/v + 1/u = 1/10 + 1/(–5) = 1/10 – 2/10 = –1/10 f = –10 cm