Question

an object that is 25cm in front of a convex mirror has an image located 17cm behind the mirror. how far behind the mirror is the image located when the object is 19cm in front of the mirror?

Please show all work, and explanation. My professor doesn't explain this well at all. Thank you!

Answer 1

let the focal length of the mirror is f

di = -17 cm

do = 25 cm

using mirror formula

1/f = 1/di + 1/do

1/f = -1/17 + 1/25

f = -53.125 cm

Now , for do = 19 cm

using mirror formula

-1/53.125 = 1/19 + 1/di

di = -14 cm

the image is located 14 cm behind the mirror