Finding distance of image from mirror given focal length

  • Thread starter RabbitWho
  • Start date
  • #1
153
18

Homework Statement


An object is at a very large distance from a concave mirror of focal length 40cm. Find the distance from the image to the mirror. Is the image real or virtual?

Homework Equations


1/u + 1/v = 1/f

The Attempt at a Solution


[/B]

1/u + 1/v = 1/40

The image has to be real because it must be outside the focus if it is very far from the mirror, right?
It seems to me like I haven't got enough information to solve the problem. How would I go about doing it? The answer from the key is 40cm.
 

Answers and Replies

  • #2
RUber
Homework Helper
1,687
344
What do you get if you put in a very large number (say, 10000cm) for the object distance? What happens as that distance gets even farther?
 

Related Threads on Finding distance of image from mirror given focal length

Replies
3
Views
2K
Replies
1
Views
8K
Replies
1
Views
9K
Replies
4
Views
2K
Replies
2
Views
32K
  • Last Post
Replies
1
Views
3K
Replies
1
Views
926
  • Last Post
Replies
6
Views
5K
Top