Experiment 9: Lenses

Purpose: To observe some of the characteristics of a converging lens when the object is placed on one side of the lens and the real inverted image is placed on the other side of the lens.

Equipment:

• Convergering lens
• Light box with outline image
• Meter stick
• 12 inch ruler
• Lens holder
• White board



Experiment:

Light Box with outline image to be projected

Physical Set up of the experiment

In the experiment we determined the focal length of the lens by using a simple visual analysis and measurement.

A focal point distance from the surface to lens was measured by holding the lens horizontally above a lamp until the light was maximized using a 12 inch ruler.

f = 5.2 ±0.5 c.m


The lens was then clamped onto a holder, and set at a distance of 1.5f, 2f, 3f, 4f, and 5f and fixed at an object height for the experiment.


This resulted in different image distance and image heights.


Table 1: Measured Data

The uncertainty was calculated using the max/min values for Magnification calcuation. And bellow is a sample calculation.  

At an object distance of 0.5f, the image was completely blurred and it bacame virtual, as shown in the image bellow

As shown in the picture above, it is completely viewable inside the lens itself.


Conclusion:

In plotting the inverse image distance vs. negative inverse object distance yileded a linear relationship confirming a correct initial focal length.

Eqs.        1/q = -m/p +b
                1/q = -1/p +1/f