The magnification produced by a converging lens

The magnification of an image is simply the ratio

height of image
height of object

The geometry of the situation means that the magnification is given also by the ratio

Check this relationship for real images

Measure the focal length of the lens you are using the parallel ray method.
Measure the diameter of the cross hair aperture (ho) using callipers
Place the cross hair “object” at a distance between 2f and f  from the lens.
Focus the image.
Measure the diameter of the image (hi) using callipers:
Measure the distances u and v
Repeat the procedure for 2 further values for u. (including at least one value of u greater than 2f)

Produce a table with the headings::

	ho   (cm)	hi    ( cm)	u   ( cm)	v  (cm)	hi/ho	v/u  	% error	
A	
							
B	
							
C	
							
D	

Now estimate the uncertainty of each of your measurements.

estimated uncertainty ho  ______________

estimated uncertainty hi  ______________

Calculate the percentage uncertainty of each measurement.

A  %ho________________________  A %hi_____________________________

A %(u)_________________________A %(v)____________________________

B  %ho________________________  B %hi_____________________________

B%(u)_________________________B %(v)____________________________ 

C %ho________________________  C %hi_____________________________

C %(u)_________________________C %(v)____________________________

D %ho________________________  D%hi_____________________________

D %(u)_________________________D %(v)____________________________

Calculate the percentage uncertainty of hi/.ho  and v/u and enter them in the final column of your table.

Does the result of your experiment conform to the expected result? 

_________________________________________________________________

Comment on the reliability of your experiment.

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________

__________________________________________________________________