Lenses

The purpose for this lab is to observe some characteristics of a converging lens when an object is placed on one side of the lens and the real, inverted image is placed on the other side of the lens.

We prepared the apparatus by placing the lens in the lens holder on the table, and then we placed the filament about 4 focal length distances from the lens. We then moved the screen back in forth to view an image and recorded our observation.

The focal length of the lens was printed on the box, which it states its f = 5cm.
-distance from center of lens to filament: d_o = 20cm
-distance from center of lens to image:    d_i  = 7.3cm
-height of filament: h_o = 9cm
-height of image :  h_i = 4.2cm
-Magnification: M = h_i/h_o = 0.45
The image was inverted and real

We then reversed the lens and observed that there is no difference.

We moved the lens about 2 focal distances from the filament and record our measurements.

-distance from center of lens to filament: d_o = 10cm
-distance from center of lens to image:    d_i  = 10.7cm
-height of filament: h_o = 9cm
-height of image :  h_i = 10cm
-Magnification: M = h_i/h_o = 1.11
The image was inverted and real


We moved the lens about 1.5 focal distances from the filament and record our measurements.

-distance from center of lens to filament: d_o = 7.5cm
-distance from center of lens to image:    d_i  = 15.7cm
-height of filament: h_o = 9cm
-height of image :  h_i = 18.5cm
-Magnification: M = h_i/h_o = 2.1
The image was inverted and real.

I predict that the image would not be as bright if half the lens is covered with masking tape. I placed the masking tape and proved my prediction.

I then made a chart with all focal points measured and a few others.

When the lens is moved at a distance of .5 f, the image is not formed because it cannot focus. Its within the focal point. If viewing the lens from the inside the image can be viewed.

Slope = 0.451
y-int = 0.1547