# I have a question about a concave mirror where the focal point is on the outside.

#### afcwestwarrior

I know that when the focal point is in the inside of a concave mirror. The focal point is greater than zero, and the radius is greater than zero and the lateral magnification is greater than zero.

So if the focal point is on the outside of this concave mirror. Would the focal point be less than zero, and would the radius be less than zero, and would the lateral magnification be less than zero.

Related Introductory Physics Homework Help News on Phys.org

#### mgb_phys

Homework Helper
Sorry not sure what you mean, the focal length of a concave mirror is half the radius of curvature.

see http://www.glenbrook.k12.il.us/GBSSCI/PHYS/class/refln/u13l3a.html [Broken]

Last edited by a moderator:

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving