# Spherical mirrors (concave), easy plug in chug, but i f'ed it up!

1. Mar 13, 2006

### mr_coffee

Hello everyone, I tried a problem on concave mirros and i have no idea why this is wrong. I was given enough info but still didn't like it. Here is the problem:
Spherical mirrors. Object O stands on the central axis of a spherical mirror. The table gives object distance p, the type of mirror, and focal distance f. Find the image distance i and the lateral magnification m of the object, including signs.

p (cm) = +25
Mirror = concave
f (cm) = *17

Find i(cm) and m.

Idon't know what the *17 means though! I just took it as a the foocal distance f = 17cm.

Any idea where i f'ed it up? thanks!

2. Mar 13, 2006

### eep

Check your math. 1/4 + 1/4 does not equal 1/8.

3. Mar 13, 2006

### mr_coffee

Ahh thanks Eep, either i drank too much coffee or not enough hah.