Transcript V 0 - umdberg

Clicker Questions for NEXUS/Physics
Electric currents
and circuits
A. Yes
B. No
C. I have no idea
NEXUS/Physics Clicker Questions
Is it possible to light a bulb
with a battery using only one wire?
Which of the arrangements shown
will light the bulb?
A. Only A
C. Only C
D. Only D
E. Only E
F. Only F
G. A & C
H. B & F
I.
D&E
NEXUS/Physics Clicker Questions
B. Only B
A.
B.
C.
D.
E.
F.
G.
H.
A in #1
B in #1
A and B in #1 (equal)
A in #2
B in #2
A and B in #2 (equal)
All 4 equal
Other
NEXUS/Physics Clicker Questions
In the two cases shown here a battery is
connected to a box containing some identical
bulbs. The battery maintains a constant
potential difference V0. across its terminals.
Which bulbs will be brighter?
Charge flows through a light bulb.
Suppose a wire is connected across the
bulb as shown. When the wire is
connected,
A. all the charge continues to flow through the
bulb.
B. half the charge flows through the wire, the other
half continues through the bulb.
C. all the charge flows through the wire.
D. none of the above
A.
B.
C.
D.
increases
decreases
decreases to 0
remains the same
NEXUS/Physics Clicker Questions
This circuit has two identical light bulbs
burning with equal brightness and a
single 12 V battery. When the switch is
closed, the brightness of bulb A
A.
B.
C.
D.
increases
decreases
decreases to 0
remains the same
NEXUS/Physics Clicker Questions
This circuit has two identical light bulbs
burning with equal brightness and a
single 12 V battery. When the switch is
closed, the brightness of bulb B
1.
2.
3.
4.
5.
6.
7.
8.
A
B
C
D
B and C
A and D
Something else
You can’t tell from the
information given
NEXUS/Physics Clicker Questions
Which of the bulbs in the following
circuit is (are) the brightest?
Sample Problem
(R)
(2R)
(3R)
(R)
(V0)
I0 = V0 /R
NEXUS/Physics Clicker Questions
• How do the currents in
resistors A and B compare?
• How do the voltage drops
across resistors A and B
compare?
• How does the current in and
voltage drop across resistor
C compare to those
in A and B?
• Find the current in resistor D.
Sample Problem
(R)
(2R)
(3R)
(R)
(V0)
I0 = V0 /R
NEXUS/Physics Clicker Questions
• If bulb D is removed
from its socket, how
does the brightness
of the three bulbs A,
B, and C change?
Sample Problem
(R)
(2R)
(3R)
(R)
(V0)
I0 = V0 /R
NEXUS/Physics Clicker Questions
• If bulb D is put back in
its socket, and now bulb
C is removed, rank the
brightness of the three
bulbs A, B, and D?
#1 = 6V
#2 = 3V
A = B = C = 3Ω
NEXUS/Physics Clicker Questions
Use Kirchhoff's principles
to find:
• the current
through each
of the bulbs and
• the current
through each
of the batteries.
What can you say about the voltage
at the points A, B, and C?
A. The magnitudes of the voltages
at A and B add up to the
magnitude of the voltage at C.
B. The sum of the magnitudes of
the voltages at two of the points
adds up to the magnitude of the
voltage at the third (but we can’t
say which).
C. The magnitude of the voltages at
all three points are equal.
D. There is not enough information
to draw any of the above
conclusions.
E. Something else.
What can you say about the currents
at the points A, B, and C?
A. The magnitudes of the currents flowing
through A and B add up to the magnitude
of the current flowing through C.
B. The sum of the magnitudes of the
currents at B and C add up to
the magnitude of the current through A.
C. The sum of the magnitudes of the
currents at A and C add up to the
magnitude of the current through B.
D. The magnitude of the currents flowing
through all three points are equal.
E. There is not enough information
to draw any of the above conclusions.
F. Something else
In what direction is the current
at point C flowing?
A. To the left.
B. To the right.
C. It is zero.
D. There is not enough
information to draw
any of the above
conclusions.
E. Something else.
What can you say about the
voltage at the point C given that
we take the voltage at the bottom
of the battery to be 0?
(V0 = 9 V; R = 3 Ω )
A.
B.
C.
D.
E.
It is zero.
It 9 Volts.
It is 3 Volts.
It is 4.5 Volts.
There is not enough
information to draw any of
the above conclusions.
F. Something else.