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    How do you answer this question michaels

    A person looks at her image in a shiny spherical decoration when

    her face is 30 cm from the surface of the decoration. The diameter

    of the decoration is 20 cm. Find the position of the image

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      The spherical decoration is the equivalent of a convex mirror - which means the centre point (C) will be half the diameter (10cm). The focal point is always half the distance between the centre and the surface, so F = 5cm. As long as you remember that the image distance and focal point are negative values, it should work out like a regular optics question.

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