Question

A convex mirror has a focal length of 18 cm. The image of an object kept in front of the mirror is half the height of the object. what is the distance of the object from the mirror ?

Answer 1

Answer:

M = h2/h1

M = 1/2

Now M = - v/u

therefore -v/u = 1/2

v = - 1/2 u = - u/2

1/v = -2/u

Now using mirror formula,...

1/v + 1/u = 1/f

-2/u + 1/u = 1/f

( -2+1 )/u = 1/18

-1/u = 1/18

therefore u = -18

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