Getting started on lab

P1.  Review quiz (in mailbox) - key is posted on blog.

Lab stuff -

2.  Make sure you have a neat data table (remember units).

3.  Make sure you have calculated the experimental focal lengths (f) using the lens equation:

1/f = 1/di + 1/do

In the lab, you'll need to show a sample calculation (from your data).  See sample below.

4. Start thinking about sources of error - also, why is your calculated f different from the f obtained by focusing an image of a tree outside onto your screen?

5.  Look at your data.  Is there a point when the images go from smaller to bigger?  Real to virtual?  Are those points related to the focal length?

On Monday, bring this work as well as your notebook for me to check.

Thanks, and have a great weekend!

Quiz key

Prepping for Tuesday's lab

The purpose of our new lab on lenses and mirrors is to determine how the distance between object (candle) and lens, the object distance (do), is related to the distance between image and lens (di).

We will also determine the effect on the image's:  relative size (bigger, smaller, same size), orientation (up or down), and whether or not the image is real (can be projected onto a card/screen) or virtual (can NOT be projected onto a card/screen - but CAN be seen through the lens).

In other words:

How does do affect di, and the various characteristic of the image formed?

In this lab, you will record the following:

do (candle distance to lens or mirror) - this will be a measured distance
di (image distance to lens or mirror) - this will be a measured distance
up or down (is image right-side up or upside-down)
relative size (bigger, smaller, or same size as original flame)
real or virtual (whether or not image is on a screen or only visible through the lens)

You will perform this experiment for each of the following optics:

convex lens
concave lens
concave mirror
convex mirror

See the picture below:

HW

Homework for Wednesday - note that we are having a quiz on Friday.  Start studying now.

1.  Think about today's informal lab again.  You have an initial angle of 60 degrees (coming from air) and are refracted to 40 degrees inside a block of some mystery material.

a.  Draw this scenario.
b.  What is the index of refraction of the mystery stuff?
c.  Now that you know the index of this stuff, what is the speed of the light inside of it?
d.  What happens to the wavelength of light inside the stuff?

2.  Research the following topic, bringing back a short definition (that you understand):  What is the focal length of a lens?

3.  If you have time, read about fiber optics and how they relate to total internal reflection (and/or the critical angle).

4.  Review the optional homework (if you did it).  There will likely be a trig question on the quiz - something that has to do with a right triangle.