how far should an object be from a converging mirror of radius 36cm to form a real image one - ninth of its size

Tabetomo asked Jan 6, 2022

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Tabetomo asked Jan 6, 2022

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11 votes

Answer:

focal length :

${ \tt{f = (r)/(2) }} \\ focal \: length = (36)/(2) = 18 \: cm$

From linear magnification:

${ \tt{ (1)/(m) + 1 = (u)/(f) }} \\ (1)/(9) + 1 = (u)/(18) \\ \\ u = (18 * 10)/(9) \\ u = 20 \: cm$

The object must be at 20 cm

Roy Cohen answered Jan 11, 2022

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