Image height of 4 cm flower in convex mirror with 25 cm focal length

[Brittany King]

1. Homework Statement

A convex spherical mirror with a focal length of magnitude 25 cm has a 4.0-cm tall flower placed 100 cm in front of it. What is the height of the image of the flower?

a.20 cm
b. 1.6 cm
c .0.80 cm
d. 4.0 cm
e. 8.0 cm

Homework Equations

1/f=1/do+1/di

M=-di/do=hi/ho

The Attempt at a Solution

[/B]
Using mirror equation I calculated di=33.3cm
Using Magnification equation I calculated hi=1.33cm

I thought this would be a simple problem, I don't see my mistake. Do any of you? Thanks in advance.

 

[BvU]

Please, show the steps in your calculation...

 

[yihloong]

you have used the correct equations, but you forget about the focal length of convex mirror is virtual, hence you should substitutes f = -25 cm, and you should get di = -20 cm , hence, hi = 0.80 cm

 

[BvU]

you have used the correct equations, but you forget about the focal length of convex mirror is virtual, hence you should substitutes f = -25 cm, and you should get di = -20 cm , hence, hi = 0.80 cm

Hello yihloong,

Please note that in PF we don't provide the answers: we help the posters learn and understand by pointing at mistakes and by asking relevant questions. Directly giving an answer often robs the poster from a valuable learning experience