Transcript Ch. 23 Electric Current

Ch. 23 Electric Current
Clicker Activities
Task
 You
will be shown four different
arrangements of light bulbs connected to
batteries with conducting wires. The
arrangements will vary with their being
between 0 and 4 light bulbs connected in
series. Assume all pieces in the circuit
behave perfectly. A voltmeter will be
used to measure the potential difference
between the terminals of the battery.
V1
V2
V3
V4
Rank the potential difference measured
between the two battery terminals from the
greatest to the least. If there are any ties
indicate them.
A.
B.
C.
D.
E.
V1 > V2 > V3 > V4
V4 > V3 > V2 > V1
V1 = V4 > V2 = V3
V1 = V2 = V3 = V4
Cannot be determined
What was the reason that you
ranked them that way?
A.
B.
C.
D.
E.
The more resistors, the more voltage
the battery supplies
The more resistors the less voltage a
battery supplies
The voltage is used by the first light
bulb, then the next …
The bulbs on the end use up the
voltage first
Ideal batteries always provide the
same voltage
How confident are you about your
answer?
A.
B.
C.
D.
E.
I know I’m right
I’m pretty sure
Neutral
I’m mostly guessing
I’m completely guessing
Task – A student builds a series circuit
with a battery and three identical light
bulbs. She correctly determines that the
circuit will draw .3 A. Between each
circuit element she inserts an ammeter.
Before closing the switch she predicts
what the reading of each ammeter will
be as shown in the next slide. What if
anything is wrong with her prediction?
.3 A
.2 A
.1 A
0.0 A
What if anything is wrong with the predicted
values of the ammeter readings?
A.
B.
C.
D.
E.
Nothing the predictions are correct
The values are correct but the order of the
readings should be reversed
The readings should all be the same
The readings should be greater on the outer
ammeters
The readings should be greater in the middle
How confident are you about your
answer?
A.
B.
C.
D.
E.
I know I’m right
I’m pretty sure
Neutral
I’m mostly guessing
I’m completely guessing
Several Circuits will be modified
by changing the number of light
bulbs. Your task will be to
predict and explain how adding
the light bulbs will change the
reading on the ammeter and the
brightness of each bulb.
Consider the following circuit. An
additional resistor will be added in
series. Answer the following
questions.
What will happen to the reading
on the ammeter?
A.
B.
C.
D.
It will increase
It will decrease
It will remain the same
Some other answer
What was your reason?
A.
B.
C.
D.
The resistance went up so less
current
More light bulbs so more
current
The battery remains the same
so no change
Some other answer
What will happen to the brightness
of each light bulb when the third one
is added?
A.
B.
C.
D.
It will remain the same.
It will increase
It will decrease
Some other answer
Consider the following circuit. A 3rd
light bulb will be added in parallel.
Answer the following questions.
What will happen to the reading
on the ammeter?
A.
B.
C.
D.
It will increase
It will decrease
It will remain the same
Some other answer
What was your reason?
A.
B.
C.
D.
The resistance went up so
less current
More light bulbs so more
current
The battery remains the same
so no change
Some other answer
What will happen to the brightness
of each light bulb when the third one
is added?
A.
B.
C.
D.
It will remain the same.
It will increase
It will decrease
Some other answer