PHYS 202 General Physics

PHYS 202 General Physics
Final Exam Review Sheet
The exam will be closed book. All necessary equations will be provided, but you may bring
a 3 × 5 card with equations written on it if you wish.
Look over the Mid-term Review Sheet for other study problems. Following are some problems
from prevous final exams. In addition, on the course’s home page there is a link for downloading
some worked-out problems in electricity. (I expect you have already downloaded this!) Finally,
review your labs!
1. For the circuit shown, calculate (A) the total current supplied by the battery, (B) the voltage
drop across the 6- Ω resistor, (C) the power dissipated by the 10- Ω resistor, and (D) the total
power supplied by the battery.
6 V
6 Ω
10 Ω 3 Ω
2. Determine the equivalent resistance between the open terminals for the group of resistors in
the drawing.
6.0 Ω
8.0 Ω
12.0 Ω
4.0 Ω
5.0 Ω
11.0 Ω
3.0 Ω
3. An electric alarm clock used a 5.0-W motor and runs all day, every day. If electricity costs
$0.10 per kWh, determine the yearly cost of running the clock.
4. A cigarette lighter in a car is just a resistor that, when turned on, is connected across the
12-V battery. Suppose a lighter dissipates 33 W of power. Find (A) the resistance of the
lighter and (B) the current that the lighter draws from the battery.
5. 30.0 m of thin platinum wire is found to have a resistance of 12.0 Ω. What would be the
resistance of 100 m of the same wire What would be the resistance of the 30-m piece if you
foled it in half and connected the ends, to form a conductor 15.0 m long
6. A certain battery is found to have a voltage of 28.0 V across the terminals when measured
with a voltmeter. (A voltmeter requires almost no current to operate.) When a 120- Ω resistor

is connected across the terminals of the battery, the voltage drop across the resistor is found
to be 25.5 V. Determine the internal resistance of the battery. Predict what the voltage
between the battery terminals would be if we hooked a 40- Ωresistor between the terminals.
7. Why can a bird sit on a high-voltage power line and not be shocked
8. Here is drawn a circuit involving a battery and a light bulb. What will happen if we “ground”
a terminal of the light bulb by hooking to a metal pipe stuck in the ground Explain.
PIPE
9. Consider the circuit below. When the resistance of the nichrome wire is decreased, what
happens to the brightness of each bulb Explain why this happens, using concepts of both
current and voltage.
A
+
-
3 V
B
Nichrome
wire
10. In the circuit shown below, the voltage across the 30- Ω resistor is 2.40 volts. Find the battery
voltage without calculating any currents.
10 Ω
+
V =
-
30 Ω
60 Ω
5 Ω
#1: (A) 0.5 A (B) 1.0 V (C) 2.5 W (D) 3.0 W
#2: 24.5 Ω
#3: $4.38
#4: 4.4 Ω, 2.8 A
#5: 3 Ω
#6: 11.8 Ω, 21.6 V
#9: 4.20 volts