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How do batteries work?  Find out and write about it in your notes.

HW - electric field

Look up the concept of electric field and determine how one draws them and what significance they have.

HW

Late post, so do these if you have time:

1.  What are each of the quantities in the Coulomb's law equation, and what are their units?

2.  a.  Calculate the force that exists between two clusters of charge (each 10 micro coulombs), 0.1-m apart.  The prefix "micro" means x 10^-6.  Be sure to use scientific notation (EE key --> 2nd comma) on your calculator).
b.  Is this force attractive or repulsive?  How do you know?

3.  If you have a cluster of charge that is 5 C in magnitude, how many protons is this?  Recall that 1 C of charge is 6.25 x 10^18 protons.

4.  Thinking about the inverse square law - if the distance between two charges is changed to five times the original distance, what exactly happens to the force between them (compared to the original force)?

5.  If the distance between two charges is changed to half the original distance, what exactly happens to the force between them (compared to the original force)?

*6.  The radius of a typical Hydrogen atom is 53 pm (5.3 x 10^-11 m) -- the distance between a proton and electron in "orbit" around it.  What is the force between these two particles?  Recall that the charge of a proton and electron is the same, though one is negative and the other is positive.

HW

Find a definition for charge, including the unit for it.

And if time, find out something about Coulomb's law.

HW to TURN IN on Thursday

1.  Find out about a few examples of how holography is used today.  Or if you're feeling ambitious, suggest some uses for it.

2.  Diffraction question

You are sending light through a diffraction grating that has 300,000 slits/openings per meter.  You aim a blue laser at it (wavelength = 475 x 10^-9 m).  The laser and grating is 1-m from a wall.  Find:

a.  the value for d (the distance between the slits)
b.  the diffraction angle for a first order (n = 1) image
c.  the distance between the central image (n = 0) and the first (n = 1) image.  Use trig here.
d.  Draw this situation.
e.  If you used a red laser, would the dot spacing change?  If so, how?

HW

Find out something about holography - what it is, how it works, applications, etc.

Diffraction

Please do a little reading about light diffraction.  Find out what it is, and if possible, find a mathematical expression that represents it.