Value of Refractive index of water for tank 1= 1. 68 Value of Refractive Index of water for tank 2=1. 35 2. What is the focal length of the lens used in section 1. 3 “Focal Length” of your manual? Can you deduce from the image seen, if the lens used was converging or diverging? The focal length of the lens used is calculated to be 31 mm. The lens used in the experiment was a converging lens as the image was 3. Calculate the focal length of the given converging lens based on the measurements of s and s ‘ and thin lens equation. Tabulate your results (for all he three trials).
Compare ratios of the image and object distances and heights for the three object distances to show-(s’ / s) = (h’ / h) is true. Draw a ray diagram and show the different lengths for one trial. The equation can be proven by using the first trial in the experiment. 2. 21 -2. 21 Real Images object s (mm) image s’ (mm) object h (mm) image h’ focal length f (mm) 140 310 430 950 96. 4 175 215 500 325 900 97. 9 220 97. 4 4. Use the parallax method described in the lab manual to determine the focal length of the lens. Compare this length to the previously calculated values.
The value of the focal length using the parallax method is 96. 4 mm. The average value of the focal length is 97. Mm . The value is approximately same. 5. Describe the virtual image seen in Section 1. 3 ‘Virtual Image” (observing an object through a converging lens). Is the image larger/smaller than the object? Is the image upright? The virtual image in this case was larger than the object as it is magnified. The image is also upright. 6. Use: s=15 CM and f -?10 CM to calculate s Show / explain why it is not possible to get a real image using your diagram and the equations above. S +1/s’= l/f Using the equation the value of s’= -6 CM. The value of s’ cannot be negative. This would mean that the image is reflected by the lens, which is not the case. 7. Calculate a value for f D (the focal length of the diverging lens) using the method described in Section 1. 4 “Lens Combinations” of the lab use the lenses as one lens, and thin lens equation to find f combined then use 1/ f combined=l/ f C+l / f D to find f D . Would this experiment be possible if C>I f DID ? Using the average value offs mentioned above, the value food is 149. 7 mm.
FCC>FDA this experiment would not be possible as there would be no image. 8. You have a lens with a focal length of 10 CM. You need to combine this lens with another, in contact, to make a combination lens with a focal length of 30 CM. What focal length should you choose for the second lens? The focal length of the second lens should be -15 CM Conclusion: This experiment looked at many techniques to obtain the image position. Human error played an important part in this experiment. The refractive index of water calculated is not the same as given, this could be because human error while measuring the angles.