4.4.3 Lab: Optics Dry Lab
Physics Sem 2
Points Possible:50
Name: Alexander Chuvaev
Date:
Optics
Materials:
Optics bench
Optics kit,
... [Show More] including a lens/mirror mount
Convex lens of known focal length
Concave mirror of known focal length
Light source/candle
Screen
Meter stick/metric ruler
Two polarized films
Prism
Laser pointer
Protractor
Graph paper
Electromagnetic spectrum chart
Materials for Exploring Further:
Plane mirror
Ripple tank, with sheet of plastic or glass that fits on part of the bottom of the
tank, and objects that can be used as boundaries to obstruct the pathway of
waves
Wave-motion rope
Tuning-fork kit
Stroboscope
Resonance-tube kit
In this lab, you will investigate the relationship between the focal lengths of a mirror
and lens and the type of image that is generated.
Procedure
Part 1: Image from a Lens
1. Place the light source, convex lens, and screen on the optics bench as
shown in figure 1. Start with the light source at a distance greater than 2ƒ
from the lens.
Figure 1
2. Measure the height of the light source, or "object" (ho), and record it in data table
1. Also measure and record the distance between the lens and the light source (do)
in the data table. Using the lens equation and the given focal length, calculate the
distance from the lens to the image (di) and the height of the image (hi):
and .
Record your calculations in the "Calculated" section of data table 1.
3. Keeping the light source and lens in the same position, turn on the light source
and adjust the screen until a clear, real image is formed on the screen. Measure the
experimentally determined di and hi, and record your observations in the
"Experimental" section of data table 1.
4. Place the light source a distance of exactly 2ƒ from the lens. Record the distance
between the lens and the light source (do) in data table 1. Using the lens equation
and the given focal length, calculate the distance from the lens to the image (di)
and the height of the image (hi). Record your calculations in the "Calculated" section
of data table 1.
5. Turn on the light source, keeping it 2ƒ from the lens, and adjust the screen until a
clear, real image is formed on the screen. Measure the experimentally determined
di and hi, and write your observations in the "Experimental" section of data table 1.
6. Place the light source at a distance of somewhere between ƒ and 2ƒ from the lens.
Record the distance between the lens and the light source (do) in the data table.
Using the lens equation and the given focal length, calculate the distance from the
lens to the image (di) and the height of the image (hi). Record your calculations in
the "Calculated" section of data table 1.
7. Keeping the light source and lens in the same position, turn on the light source
and adjust the screen until a clear, real image is formed on the screen. Measure the
experimentally determined di and hi, and write your observations in the
"Experimental" section of data table 1.
Data Table 1
ho = 1.5 cm
ƒ = 25 cm
Calculated
results
Calculated
results
Experimental
results
Experimental
results
di hi di hi
Greater than 2ƒ
do = 54 cm 46cm -.56cm 46.4 cm 1.3 cm
2ƒ
do = 50 cm 48cm -.64cm 49.5 cm 1.4 cm
Between ƒ
and 2ƒ
do = 42 cm 61cm -.96cm 61.5 cm 2.1 cm
Part 2: Image from a Mirror
8. Repeat steps 1 - 7, this time using the concave mirror. Be sure to angle
the mirror to project the image onto the screen, as shown in figure 2.
Record your calculations and measurements in data table 2.
Figure 2
Data Table 2
ho = 1.5 cm
ƒ = 25 cm
Calculated
results
Calculated
results
Experimental
results
Experimental
results
di hi di hi
Greater than 2ƒ
do = 60 cm 43cm 1.1cm 43.1 cm 1.2 cm
2ƒ
do = 50 cm 48cm -.86cm 48.5 cm 1.5 cm
Between ƒ
and 2ƒ
do = 46 cm 54cm 1.7cm 54.5 cm 1.8 cm
Part 3: Observing Polarization and Refraction
9. Place a polarized film over the light source. Place another polarized film
on top of the first. Slowly turn the second film while keeping the first film
stationary. Notice what happens to the brightness of the light.
10. Remove the polarized films. Place a prism over the light source. Turn
the prism until you can see a rainbow.
11. Direct a laser pointer toward the prism at an angle, as shown in figure
3. Trace the shape [Show Less]