WoRKSH EET on ERIES and PnrALLEL LiRUTS
(A)
V= vo ltuge
I
curent
1,5A
6V
(a)V
()
I
c)
()
(B)
I
(e)
V
g)I
3.0A
ExAMINE THE FOLLOHING CIRCUIT DIAGRAM.
41
e) What would
happen to the
total current if a
lightbulb is
added in series
with the battery?
The brightness
A. WHAT HOULD BE THE READINGS ON THE FOLLOWING AMMET ERSs/voLTMETERS? of each bulb?
life of the
battery?
2
V
(
)
T
-I=
I=bA
B.
43
Y
V
HAS UNSCREWED,
IF BULB#2
THO BULES?
HHAT WOULD BE
THE
EFFECT
ON
THE
OTHER
WHY?
C. WHAT HOULD YOU PREDICT WOULD HAPPEN TO THE TOTAL CURRENT IN THIS
CIRCUIT
IF
A FOURTH BULB IS
EXPLAIN WHY?
ADDED IN PARALLEL,TO, THE OTHER BULBS?
WhaF Jould happen to the life ef he batery
What would happen to the life of the battery?
D. Ass UMING
THAT BULBS
1,2,AND
ALL BE THE SAME BRICHTNESS?
What
will happen
fe
3 ARE ALL
EXPLAIN.
IDENTICAL,
the total Curet it
a
?
HOULD THEY
f) Where would
you install a fuse
to protect the
whole circuit?
g) How would
the total power
consumption
change in (C)
and (e)?
lvghtbolb uwovld be
addecd in
nes t h the batBery ? Srghtness of tach bulb) lfe of he bateg?
tWhere wovld you insta!l
a
fuse to protect he hole Cidvit
Describe and explain what would happen in the
circuit diagram shown below if
a) the switch is closed
b) the switch is closed and light bulb number 2
is unscrewed
c) the switch is closed and light bulb number 5
is unscrewed
d) the switch is closed, and light bulb number
4 is removed and replaced by a copper wire
e
which loads are connetedin senes.
arallel ?2
1)aleubke
) R,R R
CCompare brigktness oB he bvles.
he
Sane
l
hght bvlbs fom 9ueshon
a) Calculahe I,,J,IT
buhs.
h
e
)Compare brightress
120 V
are
Connected in
Senes
1)a) In the following circuit, calculate the current and voltage drop across in 3.0 N resistor.
b) calculate the power usage in 20 resistor.
20
ww
ww
32
m
12
19V
c)What will happen to the voltage drop across the 10 resistorifyou add a 2 0 resistor in series to the 3 Q
resistor? Answer
qualitatively and Explain.
2)An electric appliance with a current of I and a resistance of R is used fort hours during the course of a month.
The cost of operating the appliance at 120-Volts is D dollars. What would be the new cost (in terms of D) if
an appliance which drew half the current at 240 Volts were used?
HIso, rennder
-f-A
Part
l: Changes in the Brightnes of Light Bulbs
Dial the power supply all the way down and keep it off and eonnect your circuit
s
shown to the right. Double check your circuit eonneetion before turning on the
power supply. To test the connection, only inerease the voltage a little bit (less thn
V)and see if the meter shows deflection and any light bulb begins to light up.
Make sure all elements in the eireuits are comected correctly before you proceed.
Carefuly observe the brightness ofthe bulbs. Close the switch, how does the
brightness of each bulb change? It the bulbs are too dinm, you nnay increase the
voltage very slightly. Do not increase the voltage so mueh that the voltmeter reads
more than 1V and don't make the bulbs very bright becmuse these bulbs blow easily - just make them bright enough for
observation, especially because brightness may inerease when you close the switch. When you close the switch:
volts
volts to
Volmeter's reading goes from
CArcle
from off to on
from on to off,
Bulb A gets:
dimmer,
same,
brighter,
from off to on
from on to oft,
Bulb B gets:
dimmer,
same,
one
brighter
3. Explain your observations:
Part
IV: Changes inthe Brightness of Light Bulbs
1. Dial the power supply all the way down and keep it off and connect your circuit as
shown to the right. Double check your circuit connection before turning on the power
supply. To test the connection, only increase the voltage a little bit (less than 1V) and
see if the meter shows deflection and any light bulb begins to light up. Make sure all
elements in the circuits are connected correctly before you proceed.
2. Carefully observe the brightness of the bulbs. Close the switclh, how does the
brightness of each bulb change? If the bulbs are too dim, you may increase the voltage
Do not increase the voltage so much that the voltmeter reads more than
A
Lo
B
very slightly.
1.5V and do not make the bulbs very bright because these bulbs blow easily - just make
them bright enough for observation, especially because brightness may increase when
close the switch:
you close the switch. When you
Voltmeter's reading goes from_
Bulb A gets:
Bulb B gets:
Bulb C gets:
volts to
brighter,
brighter,
same,
dimmer,
same,
dimmer,
brighter,
same,
dimmer,
3. Explain your observations:
volts
from on to off,.
from off to on
from on to off, .
from on to off,
from offto on
from off to on
Crcle
one