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Please help me to find the answers ..........................An object is placed in front of a concave mirror of focal length 20 cm . The image formed is three times the size of the object . Calculate two possible distance of the object from the mirror. |
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Answer» Mirror: CONCAVE. Focal LENGTH = -20cm h'=3h According to magnification formula, -v/u=h'/h -v/u=3h/h -v/u=3 -v=3u v= -3u According to mirror formula, 1/f=1/v+1/u 1/-20= 1/-3u+1/u -1/20= -1/3u+(1/u)×3/3 -1/20= -1/3u+3/3u -1/20= (-1+3)/3u -1/20= 2/3u -1×3u=2×20 -3u=40 u=40/-3 u= -40/3 u= -13.33m |
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