# Mirror equation

1. Dec 13, 2007

### rhxoehwhfh

I still find these stuff hard, I have 2 question to ask about...

1. Use the mirror equation to find the image location and the height of an object placed at the centre of curvature of a concave mirror. Also find the magnification. Hint: What is the relation between the focal length and the object distance, d, for this situation?

2. Using the mirror equation and the magnification equation, find the four properties of the image formed in a concave mirror with a focal length of 50 cm, if the object is 1.5 m from the mirror and is 2.5 cm high.

Can anyone help me and show step by step how to solve these questions?,,, I really am having a difficulties... please..

2. Dec 13, 2007

### rhxoehwhfh

for second question, i tried and got this
. Mirror equation
1/f = 1/do + 1/di
1/50= 1/1.5 + 1/di
di= -1.546 cm do= 1.5cm
Magnification equation
hi/ho = - di/do
hi/2.5 = -1.546/ 1.5
hi =2.576 cm ho= 2.5cm
is this right?

3. Dec 13, 2007

### cryptoguy

for #1, the center of curvature is 2 x the focal length so you can say d = 2f.
Now plug that into the 1/f = 1/d + 1/di

For magnification, use the equation you provided.