USEFUL CONSTANTS: q (electron) =
-1.6 x 10-19 C
5] A small night light operates with a
of 50 milliamps. If the light is turned on for 8.0
hours, how much charge moved through the filament?
Answer: 1.4 x 103
6] The filament of an automobile parking
bulb develops 25 watts of power when connected
to the car’s 12 V battery. What is the resistance of the filament when operated under these
conditions? Would the resistance of the filament be the same when the bulb is disconnected
(no current flowing through it)?
Answer: 5.7 W
1] Find the currents I1 , I2 , and I3 for the circuit shown below
ANSWER: I1 = +1.0 A , I2 = -1.0 A , I3 = 0.0 A
2] Find the equivalent resistance between points a and b
for the resistor combination shown below.
All resistors have a value of 1.0 Ohm.
ANSWER: R equivalent = 1.6 Ohm or 8/5 Ohm
8] The filament of an automobile parking
bulb develops 25 watts of power when
connected to the car’s 12 V battery. If the filament is made of tungsten wire
(r = 5.6 x 10-8 W m) with a cross sectional area of 3.2 x 10-7 m2 , how long is the wire?
(remember, there are lots of little coils in filaments)
Answer: 33 meters
conservation of electricity
b) conservation of mass
c) conservation of charge
d) conservation of energy
e) conservation of momentum