1.) (a) A 150-W light bulb is hooked up to a standard 120-V wall outlet.  Find the  current in the bulb in amperes.
 

     (b) Determine the resistance of the bulb at this level of current.
 

2.)(a) Copper has a resistivity (r) of 1.68 x 10^-6 W -cm at 20°C and a temperature coefficient of resistance (a) of 0.0068/°C.   If an 8 m length of       copper wire has cross-sectional area of 10-4 cm², determine its electrical resistance at 20°C.
 

(b) Determine the resistance at 0°C of a copper wirewound resistor having a resistance of 105 W at room temperature (20°C).
 

 3.) For the circuit shown at the right, determine the
equivalent capacitance and the total charge on
it.  Also determine the charge and voltage across
each capacitor in the figure.
C₁ = 6.0 mF  C₂ = 4.0 mF  C₃ = 10.0 mF

Ceq = ________ mF   Qeq = ________ mC

Q1 = ________ mC     V1 = ________ V

Q2 = ________ mC     V2 = ________ V

Q3 = ________ mC     V3 = ________ V
 

4.) If a 3 mF capacitor is connected to a 12 V battery, determine the work done by the battery in  charging the capacitor.  Also, determine how much energy is stored in the capacitor.
 

5.) (a) Charge q₁ = 8 mC is placed 4 cm to the left of charge q₂ = 6 mC.  Draw a picture and determine the electrostatic potential at a point A located 3 cm directly above q₁.
 

(b) Determine the potential energy of this two-charge system.
 

6.) Determine the electric force  (magnitude and direction) on a 10 mC point charge  placed midway between a +5 mC point charge (left side) and a +3 mC point  charge (right side) which are located 10 cm apart.
 

7.) For the charge configuration shown to the right,
q₁ = 5 mC, q₂ = -2 mC, and q₃ = -8 mC.  Determine
the resultant electric field (magnitude and direction)
at the fourth corner of the rectangle.         HINT:
Place the origin of coordinates at this fourth corner.