pre-quiz practice

1.  Recall the electric field concept.  Draw the field that you would see under these circumstances.  The first two were shown in class:

a.  a positive hunk of charge by itself

b.  a negative hunk of charge by itself

c.  2 hunks of charge close to each other; both are negative

d.  2 hunks of charge close to each other; both are positive

e.  a hunk of positive charge close to a hunk of negative charge

If you want to know quickly if your answers a close to correct, do a google image search for "electric field".  The first few images that show up will have these among them.

2.  Review for quiz:

a.  Calculate the force between 2 charges (5E-6 C, -15E-6 C), when separated by a distance of 0.004 m.

b.  If the distance between these 2 charges were changed to 5 time the original amount, how would the force be different?  Do this without a formal calculation.

c.  Consider the 5E-6 coulomb charge.  How many protons is this?  Recall that 1 proton has a charge of 1.6E-19 C.

d.  What does it mean to be a fundamental particle?