Spherical Mirrors an ray diagram

[Pius]

Homework Statement

When an object is located very far away from a convex mirror, the image of the object is 18 cm behind the mirror. Using a ray diagram drawn to scale determine where the image is located when the object is placed 9.0 cm in front of this mirror. Note that the mirror must be drawn to scale also. In your drawing, assume that the height of the object is 3.0 cm.

Homework Equations

hi/h0=[-di/d0=di-f/f] 1/di=1/f-1/di
di/d0=di/f-1 1/di+1/di=f

The Attempt at a Solution

d0=infinite
1/infinite+1/di=1/f
f=-18.0 cm

d0=9.00cm
1/9.00+1/di=1/-18
di=-18

-18/9=hi/3
hi= -6.00cm

?!but when I draw this it doesn't equal to -6cm

 

[rl.bhat]

d0=9.00cm
1/9.00+1/di=1/-18
di=-18
Check this calculation.

 

[Pius]

Yush! It worked! Thanks a bunch!