# Electric currents and circuits

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Electric currents and circuits

Is it possible to light a bulb with a battery using only one wire?
Yes No I have no idea NEXUS/Physics Clicker Questions

Which of the arrangements shown will light the bulb?
Only A Only B Only C Only D Only E Only F A & C B & F D & E NEXUS/Physics Clicker Questions

Physics 122 4/6/2017 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? 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 Prof. E. F. Redish

Charge flows through a light bulb
Charge flows through a light bulb. Suppose a wire is connected across the bulb as shown. When the wire is connected, all the charge continues to flow through the bulb. half the charge flows through the wire, the other half continues through the bulb. all the charge flows through the wire. none of the above

Physics 132 4/6/2017 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 increases decreases decreases to 0 remains the same NEXUS/Physics Clicker Questions Prof. E. F. Redish

Physics 132 4/6/2017 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 increases decreases decreases to 0 remains the same NEXUS/Physics Clicker Questions Prof. E. F. Redish

Which of the bulbs in the following circuit is (are) the brightest?
D B and C A and D Something else You can’t tell from the information given NEXUS/Physics Clicker Questions

Sample Problem How do the currents in resistors A and B compare?
Physics 132 4/6/2017 Sample Problem 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. (R) (2R) (3R) NEXUS/Physics Clicker Questions (R) (V0) I0 = V0 /R Prof. E. F. Redish

Physics 132 4/6/2017 Sample Problem If bulb D is removed from its socket, how does the brightness of the three bulbs A, B, and C change? (R) (2R) (3R) NEXUS/Physics Clicker Questions (R) (V0) I0 = V0 /R Prof. E. F. Redish

Physics 132 4/6/2017 Sample Problem 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? (R) (2R) (3R) NEXUS/Physics Clicker Questions (R) (V0) I0 = V0 /R Prof. E. F. Redish

Use Kirchhoff's principles to find:
the current through each of the bulbs and the current through each of the batteries. NEXUS/Physics Clicker Questions #1 = 6V #2 = 3V A = B = C = 3Ω

What can you say about the voltage at the points A, B, and C?
The magnitudes of the voltages at A and B add up to the magnitude of the voltage at C. 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). The magnitude of the voltages at all three points are equal. There is not enough information to draw any of the above conclusions. Something else.

What can you say about the currents at the points A, B, and C?
The magnitudes of the currents flowing through A and B add up to the magnitude of the current flowing through C. The sum of the magnitudes of the currents at B and C add up to the magnitude of the current through A. The sum of the magnitudes of the currents at A and C add up to the magnitude of the current through B. The magnitude of the currents flowing through all three points are equal. There is not enough information to draw any of the above conclusions. Something else

In what direction is the current at point C flowing?
To the left. To the right. It is zero. There is not enough information to draw any of the above conclusions. 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 ) 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. Something else.