Pre-class test FISI-3171

Exam 2
Sep. 29, 2009
Dr. LU
(Write your answers on the answer sheets.)
1. Who developed the first electric battery? (5 points)
c) Volta.
d) Gauss.
a) Newton. b) Ohm.
2. The kilowatt-hour is a unit of (5 points)
a) charge. b) energy. c) power.
d) current.
3. A time constant is equal to: (5 points)
a) RC.
b) R/C.
c) C/R.
d) 1/(RC).
4. All magnets will have a north and south pole. (5 points)
a) True.
b) False.
5. (a) Determine the resistance of, and current through, a 75-W lightbulb connected
to its proper source voltage of 110 V. (b) Repeat for a 440-W bulb. (20 points)
6. Calculate the peak current in a 2.7-k resistor connected to a 220-V rms ac
source. (20 points)
7. Calculate currents I, I1, I2 in the right
circuit. (20 points)
8. (a) What is the force per meter of length on a straight wire carrying a 9.40-A
current when perpendicular to a 0.90-T uniform magnetic field? (b) What if the
angle between the wire and field is 35.0°? (20 points)
Bonus problem (20 points)
Calculate currents I1, I2, I3 and in the left