ringelos Posted March 5, 2012 Share Posted March 5, 2012 I am having serious trouble with this question and I'm hoping to get some assistance with it. The question goes as follows: Suppose a lens with a focal length of 10.0cm produces an inverted image half the size of a 4.0cm object. How far apart are the object and image? Show all your work. Any help is appreciated. Link to comment Share on other sites More sharing options...
rktpro Posted March 5, 2012 Share Posted March 5, 2012 I am having serious trouble with this question and I'm hoping to get some assistance with it. The question goes as follows: Suppose a lens with a focal length of 10.0cm produces an inverted image half the size of a 4.0cm object. How far apart are the object and image? Show all your work. Any help is appreciated. What you need to know is- Magnification The lens formula Just a google for that. 1 Link to comment Share on other sites More sharing options...
ringelos Posted March 5, 2012 Author Share Posted March 5, 2012 I think I have got to something. From what I can tell, we have a hi=2 and a ho=4 and a focal length that doesnt fit into the equation. Is this correct? So m= 2/4 = -di/do m= 0.5 If I am correct we now have magnification - now what? Do we multiply our focal length by 0.5 to get a value, then add said value to our focal length? So, 10x0.5 = 5, 10+5 = 15 Link to comment Share on other sites More sharing options...
rktpro Posted March 5, 2012 Share Posted March 5, 2012 I think I have got to something. From what I can tell, we have a hi=2 and a ho=4 and a focal length that doesnt fit into the equation. Is this correct? So m= 2/4 = -di/do m= 0.5 If I am correct we now have magnification - now what? Do we multiply our focal length by 0.5 to get a value, then add said value to our focal length? So, 10x0.5 = 5, 10+5 = 15 Here it goes, The focal length given is 10 cm. Because the lens has not been specified, it is obvious that focal length= +10cm and the lens is a convex lens. Now you must know that, magnification=v/u= image height/object height. [hint: remember to use sign convention. Perpendicular distances downward to principle axis are negative] Thus, say you get magnification=v/u= x. Now v = ux where x has some value. Put this in 1/v-1/u=1/f , that is the lens formula. Remember to use sign convention where ever you plug values. 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now