Question

an object is 375mm in front of a concave mirror that is the focus of 250mm. if the object is moved 25mm approached the mirror, the image will be shifted as far

Answer 1

Use the mirror formula and finid the solution.

Answer 2

how to solve that?

Answer 3

For concave mirror, foacl length is negative. Object distance always negative. The mirror formula is:
(1/u) + (1/v) = (1/f)
where, u = object distance, v = image distance, and f = focal length
Better to convert all units in terms of "metres".

Answer 4

(1/s)+(1/s') = (1/f)
(1/s') = (1/f)-(1/s)

(1/s') = (1/-250)-(1/375)
(1/s') = -(1/150) or - 0.00667 mm

when the object moved 25 mm
object -> 375 mm - 25 mm = 350 mm

(1/s)+(1/s') = (1/f)
(1/s') = (1/f)-(1/s)

(1/s') = (1/-250)-(1/350)
(1/s') = - 0.00686 mm

\[\Delta s' = -0.00667 mm - (-0.00686 mm) \]So the image object moved -> 0.00019 mm