Ch23 Review:
V=IR
P=IV,
R
2
P=1
Read Ch 23; start with the study guide
Review the powerpoint on my website
Go to www.physicsclassroom.com for extra help
1.
Explain how voltage, current and resistance behave in series wiring compared to parallel wiring.
2
Explain advantages and disadvantages of series wiring and of parallel wiring
3. How do you connect an ammeter in a circuit?
4. How do you connect a voltmeter in a circuit?
5. A lot of the problems in the book are words; you should be able to draw a schematic for any
description. Draw schematics for all the word problems in the Ch23 Supplemental Problems.
6. How do fuses and circuit breakers protect circuits?
7.
Can you analyze a circuit and determine whether the circuit breaker will pop, i.e. will the total
current exceed the allowed amperage?
a. A circuit contains six 60W lamps with a resistance of 240 ohms each, and a 10 ohm
heater. These are all connected parallel to each other. The voltage supplied is 120V.
Find the total current if
i. 4 lamps are turned on
ii. All 6 lamps are turned on
iii. Everything is turned on.
b.
8.
Will a 12 A circuit breaker ‘pop’ open if
i. Everything is turned on?
ii. Ifjust the heater is turned on?
Can you predict the brightness of bulbs if switches are opened or closed? Review worksheet
distributed in class
a. What one aspect of electricity determines the brightness of a bulb? (don’t just say ‘if it
gets electricity or not’)
9.
htn of the bulbs in this circuit. Describe what happens if you disconnect each
brig5
Rate the 5
bulb, and explain WHY.
00
10. Analyze the Power dissipated by each bulb in the circuit above
11. A 60 W bulb and a 100W bulb are wired in parallel and connected to a 120 V source. Which one
is brighter and Why?
12, A parallel circuit has 4 branches Coming off the main branch with currents of l2OmA, 250 mA,
380 mA, and 2.1 A. What is the current in the main branch?
13. A series circuit has 4 resistors, The current through One resistor is 810 mA, What is the total
current in the Circuit?
ne of each bulb in this circuit and explain why,
5
14. Rank the 5
bright
15. You should be able to determine total i.e. equival resistance for a group of resistors in series,
and for a group of resistors in parallel,
Date
Period
—
Name
CHAPTIER
niiPrpb1ems
t
Series and Parallel Cir
cuits
1.
Three 12.0-fl resistors are
connected in
series to a 50.0-V power
source.
a.. What is the equivalent
resistance of the
circuit?
Ii. What is the current in
the circuit?
C. What is the voltage
drop across each
resistor?
2. Three 15.0-fl resistor
s are connected in
parallel to a 45.0-V power
source.
a. What is the equivalent
resistance of the
circUit?
b
What is the current in the
circuit?
c. What is the current thro
ugh each resistor?
3. Two resistors are
connected in series to a
pow
er source. The voltage dro
p across the
first resistor is 5.40 V and
the voltage drop
across the second resistor
is 9,80 V. The
current through the circuit
is 1.20 A.
a. What is the resistance
of each of the
resistors?
b. What is the equivalent
resistance of the
circuit?
4. What is the equival
ent resistance of the
circuit shown below? Wh
at is the current
in the circuit? What is the
voltage drop
across the two resistors
wired in parallel?
5. A 10.0-fl resistor,
a 20.0-fl resistor, and a
30.0-fl
resistor are wired in par
allel and
connected to a 15.0-V pow
er source. What
is the equivalent resistan
ce of the circuit?
6. A 12-fl and an 18-fl
resistor are connected
to a 48-V power source.
a. What is the equivalent
resistance of the
circuit if the resistors are
connected in
series?
b. What is the equivalent
resistance of the
circuit if the resistors are
connected in
parallel?
A voltage divider is mad
e from a 9.0-V bat
tery. Two resistors are
connected in series to
the battery If one resistor
has a resistance of
24 fi and the voltage dro
p across the other
resistor must be 4.0 V, wha
t is the resistance
of the second resistor?
8. A circuit is constructed
, as shown in the
figure below. The voltme
ter reads 63.0 V.
a. Which resistor diss
ipates the most
energy per second?
b What is the voltage
of the power source?
88 f
+
120V
120.
120.
9. Three identical resi
stors are connected in
parallel across a power
source. Their equivi
lent resistance is 8.00
il. \‘Vhat is the resis
tance of each resistor?
Physics: Principles and Pro
blems
Supplemental Problems
45