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Calculate the distance of an object of height h from a concave mirror of radius of curvature 20 cm, so as to obtain a real image of magnification 2. Find the location of image also |
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Answer» SOLUTION :As per question the radius of curvature of CONCAVE mirror R = - 20 CM, hence its focal LENGTH `f = R/2 = -10 cm`, and magnification of real image `m=-2` As, `m=-v/u`, hence, `-v/u =-2` or v= 2u So, from mirror formula `1/v + 1/u = 1/f`, we have and `1/(2u) + 1/u =1/(-10) rArr 3/(2u) =-1/10 rArr u=-15 cm` and `v=2u=2 xx (-15) = -30 cm` Thus, the object is placed in front of mirror at a distance of 15 cm from it and its real, magnified and inverted image is formed at a distance of 30 cm in front of the mirror. |
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