Thin Lens Pre-Lab                     Name:

 

Object Distance

Distance of the object being observed to the lens

 

“p” is the object distance, do

“o” is the object distance, do

Image Distance

Distance from the lens to the position where the image is formed

 

“i” is the image distance, di

“q” is the image distance, di

 

 

Tables 1 and 2:  The lens, screen (image), and lighted arrow (object) are placed on the optical bench; the scale of the optical bench starts at position 0 cm and goes to 125 cm.  Below is data for the positions of the lens and the image that is formed on the screen.  Please use the fixed position of the lighted arrow as 3 cm in all cases.

 

 

Table 1: Positions of the lens and screen

Table 2: Combination of Lenses

Solve for the

focal length?

1

=

1

+

1

 

 

 

 

 

 

f

do

di

Solve for the effective focal length of the below lens combinations?

1

=

1

+

1

 

 

 

 

 

 

feffective_AB

fA

fB

lens

screen

lens

screen

fRed

fGreen

fWhite

15.0 cm

30.0 cm

18.0 cm

50.0 cm

10.0 cm

20.0 cm

-15.0 cm

Hint:   

di = 30 – 15 cm

do =

 

 

 

 

 

 

 

fRG =

 

fRW =

 

fGW =

 

 

Show work for all focal length calculations!!!

 

Table 3: Data and Results

(complete table below as requested by the lab manual)

Positions of the lens and screen

Results from Lens Measurements

Lens

xlens (cm)

xscreen (cm)

hi (cm)

hi/ho

di (cm)

do (cm)

di/do

f (cm)

R

16.2

37.8

2.6

 

 

 

 

 

G

31.2

74.6

2.5

 

 

 

 

 

W

 

 

 

 

 

 

 

 

RW

28.3

80.6

3.3

 

 

 

 

 

Position of lighted arrow, xarrow

3.0 cm

Height of arrow, ho

1.6 cm