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★An object high forms a virtual image of high, when placed in front of a convex mirror at a distance of . Calculate :- (i) the position of the image (ii) the focal length of the convex mirror. •nσ ѕpαmmíng•ѕtєp wíѕє єхplαnαtíσn nєєdєd |
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Answer» GIVEN:- object height (h) = 5cm image height (h') = 1.25cm position of image (v) = ? focal length (f) = ? (a) MAGNIFICATION (M) = (h')/h = (-v)/u Substituting the known values :- 1.25/5 = -v/(-25) 5(-v) = 1.25(-25) -5v = -30 v = -30/-5 v = 30/5 v = 6cm •°• Image is formed 6cm in front of the mirror. (b) Mirror formula = 1/v + 1/u = 1/f 1/f = 1/6 + 1/(-24) 1/f = 1/6 - 1/24 1/f = (24 - 6)/144 1/f = 18/144 1/f = 9/72 1/f = 1/8 f = 8cm •°• Focal length of mirror is 8cm= 6cm Hey Kalash HRU |
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