Question

questions 1, 2, 3, 4, and 5 with data below.

Lenses and Mirrors: Insight into Eyesight- our eyes and car mirrors. Part 1. Measure the object and image distances to find the focal distance and magnification for two convex lenses and 1 convex mirror. Table 12-1a. Measure the object and image distance to find the principal foaal distance and magnification. Lens 1 Object Distance Image DistancePrincipal Fo Magnification Length f(m) M-dvd N/A- 9./2 O.IS O-lo 4 0-4 0.2 o.1o 023 o.lo 0.1227 6.112 10 o.ll2 Average Table 12-1b. Measure the object and image distance to find the principal focal distance and magnification. Lens 2 Object Distance Image Distance Principal Focal agnification d, (m) do (m) Length f (m) 0.611 0.30l 0.29 0-242 o.200 0.193 3.09s 100 3 6.5975 o.424 o. 6 . 2.73 o. 226 0.20o o.(只 10 0 Average After completing Table 12-la for Lens I use Microsoft Excel to plot the magnification, M, vs. the object ualude the annronriate equation fit or trend line Repeat for the Microsoft Excel plot for Table 12-lb for Lens 2. Table 12-1c. Measure the object and image distance to find the principal focal distance and magnification. Concave miror conrn Mirror Object Distance Image DistancePrincipal Focal Magnification Length f(m) di (m) do (m) 0.I 0.2 o,3 N IA 0.26 4 0.2 O, 67 -38 O-3 33 0.6 지y 0.27 0.27 o.27 o.28 o, 6 0 Soo O, . 400 2-3-7 10 o37 , 27 Average After completing Table 12-1c for the mirror, use Microsoft Excel to plot the magnification, M, vs, the object distance, do (m). Include the appropriate equation fit or trend line. Part 2. Find your lens power like an optometrist. Use the average focal distances in part 1 to determine the power of each lens. Lens 2 6. QUESTIONS (Use extra sheets if necessary) 1) Based on your results in Part 1, does a real image show the object in the same orientation? What challenge does this present the retina when transmitting image information to the brain? What differences can you discern in the images formed by a convex lens compared to a convex mirror? 2) Calculate the percent difference in lens power for the two lenses provided by your instructor. 3) Does the convex lens or mirror magnification, M, increase or decrease with th Would the behavior of a concave lens or mirror be similar or different? Why or e object distance? 4) why not?

Answer 1

1. The images in part I are all upright images, (no value of magnification is negative). A real image is never upright. The retina receives the image in parts and the brain combines these parts to obtain the image. The brain erects the image.

2. Convex lenses converge the rays and focus them on the other side as that of as the object, hence always form real images, only except for when the object is placed too close to the lens i.e. between the lens and the principal focus.

Convex mirrors, on the other hand, diverge the real rays and focus the back traced rays on the other side of the mirror, hence form virtual images.

It must be noted here that the image when formed on the same side is real in case of a mirror and virtual in case of a lens.

3.

Percent difference is given by

P-P 100 Pav aug

$\mid P_1 - P_2\mid = 3.33$ and   

16.67 Pi + P2 Pau

Percent difference =
3.33 x 335 × 100
%

4. The focal length is always a constant for a given lens/mirror, so the magnification is inversely proportional to the object distance.

The behavior of a convex lens and a mirror is similar, both of them converge the rays (incident on one side) on some point on the other side, the difference is that in case of the lens this image is real and in case of the mirror this image is virtual. (in case of mirrors image on the same side as the object/observer is considered real.)