1) A charge of +0.06 C resides on an electrical component of a computer.  A distance 2 cm away a second component has a charge of +0.08 C.
 a) What will be the electric field at a point in a cpu chip located exactly halfway between the two charges?

b) What will be the electrical force between these two charges?

2) The electrons in a beam inside a TV set have a velocity of 1x107 m/s. Suppose these electrons are traveling North (they go from the back of the tube to the front). An electric field inside the tube is used to bend the path of the beam. The electric field is pointing West and has a magnitude of 100N/C.
me = 9.11x10-31 kg        e = 1.6x10-19 C
a)  Carefully draw a picture indicating the approximate path the electrons will take when the field is turned on (assuming they still hit the screen at the front of the set).

b)What will be the acceleration of the electron due to the electric field?

c) Assume North is the y-direction and East is the x-direction. What are the x and y velocities after 5x10-7 s?

3) An electron enters the magnetic field of a mass spectrometer and travels in a circle. a) If the radius of the circle is found to be 2.0 m and the electron is traveling at 3x105 m/s, what must be the magnetic field at that location?  b) Draw a careful picture indicating the direction of all of the vectors involved.   me = 9.11x10-31 kg         e = 1.6x10-19 C

4) Suppose the volume charge density on a nerve axon (cylindrical in shape with radius 0.002m) is given by    r =  5  C/m3 .
a)  Calculate the total charge on the axon for a length of 0.5m.

b)  Use Gauss' Law to find the electric field as a function of r outside the axon .

c)  Use Gauss' Law to find the electric field as a function of r inside the axon (this is NOT a conductor).

5) You are doing a biology experiment to determine whether ducks navigate using the earth's magnetic field or not.  To counteract the earth's magnetic field you use 100 turns of wire in a circular coil of radius 0.08 m.
a)  Assuming the coil is in the plane of the table, how much current do you need to equal the earth's field of 3x10-5 T at the center of the coil?

b)  Looking down onto the coil, which direction must the current flow (the created field must point upwards to counteract the earth's field which points down)?

6) A long straight wire carries a current of 5 A along the x-axis.  a second long straight wire carries a current of 10 A along the y-axis.  What is the magnetic field (magnitude and direction) at the point x = 1m, y = 1.5m?
 

7) Use Ampere's law to find the magnetic field inside a toroid (donut shape- inside the donut not inside the donut hole) of radius 10 cm with 100 loops of wire on it carrying a current of 3 amps.  Hint:  Remember to locate your Amperian loop where you want to determine the field.
 

Bonus (answer on the reverse side):
a) Describe what scientists learned from Faradayís ice pail experiment.
b) Explain how an electrostatic
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