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## Homework Statement

In front of a spherical concave mirror of radius 39cm, you position and object of height 0.6cm somewhere along the principal axis. The resultant image has a height of 0.2cm, How far from the mirror is the object located?

What if this were a convex mirror with the same radius, and the same image and object height?

## Homework Equations

1/f=1/Di+1/Do

M=Hi/Ho= -Di/Do

F=1/2R

## The Attempt at a Solution

1/2R=19.5cm focal point

I have two equations with two unknowns (Di and Do). I used the equation Hi/Ho=-Di/Do to solve the equation for -Di, getting 0.2/0.6= 1/3. 1/3=-Di/Do, solving for Di I get -1/3Do=Di.

I then just plug this equation into the mirror equation

1/do+1/(-1/3do)=1/f..... I bring the -3 from the denominator into the numerator

1/f is 2/39

1/d0-3/do=2/39

-2/do=2/39

do=-39cm

I follow the same process for a convex mirror but I get a positive answer with the same value of 39. I dont think a negative answer makes sense, and I am unsure of my sign usage... I find it odd that my object distance is the same as my mirrors radius.

Thank you in advance for the help.