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at what diatance from concave mirror of focal length 10 cm should an object 2 cm long be placed in order to get an erect image 6 cm |
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Answer» >Given Focal length of concave mirror f = -10 cm Height of the object ho = 2 cm Height of the image hi = 6 cm We need to find the object distance So we know that Magnification m = hi/ho = 6/2 = 3 (erect image) m = -v/u 3 = -v/u ⇒ v = -3u Mirror FORMULA: 1/v + 1/u = 1/f 1/(-3u) + 1/u = 1/(-10) ⇒ u = -20/3 = -6.7 cm So At -6.7cm distance from a concave mirror of focal length 10cm should an object 2cm long be placed in order to GET an erect image 6cm tall. |
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