Physics / Adv Physics
Name __________________________________________________ Hr. ___
Practice Worksheet
Combination Circuits, My solutions start on page 7
Here is a circuit for you to solve:
1. First find the Req. You might find it helpful to redraw the circuit a few times.
Req = _______________________ Ohms
2. Now find the current leaving the battery, Ib, if Vb = 9V.
Ib = ________________________ Amperes
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3. I have placed two voltmeters into the circuit. First, find the voltage drop across the 70 Ohm resistor.
Voltage drop = ____________________ V
4. You can now calculate the voltage across the 60 Ω + 10 Ω branch (hint, think about Vb and the voltage
drop you just found in the previous problem). This is showed symbolically by the second voltmeter.
Voltage drop = ___________________ V
5. Using Ohm’s Law, you can now mathematically find the current through this branch. This is
symbolically shown by the ammeter.
Current = ____________________ Amperes
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A second circuit…
Consider the combination circuit in the diagram at the right.
Use the diagram to answer the following questions.
_____ 1. The current at location A is _____ (greater than,
equal to, less than) the current at location B.
a) greater than
b) equal to
c) less than
_____ 2. The current at location B is _____ (greater than,
equal to, less than) the current at location E.
a) greater than
b) equal to
c) less than
_____ 3. The current at location G is _____ (greater than, equal to, less than) the current at location F.
a) greater than
b) equal to
c) less than
_____ 4. The current at location E is _____ (greater than, equal to, less than) the current at location G.
a) greater than
b) equal to
c) less than
_____ 5. The current at location B is _____ (greater than, equal to, less than) the current at location F.
a) greater than
b) equal to
c) less than
_____ 6. The current at location A is _____ (greater than, equal to, less than) the current at location L.
a) greater than
b) equal to
c) less than
_____ 7. The current at location H is _____ (greater than, equal to, less than) the current at location I.
a) greater than
b) equal to
c) less than
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Here is the same circuit as on the previous page. Now, though,
let’s say that we move a voltmeter around the circuit. We
measure the voltage (reading from the voltmeter) across the
batteries and then across each resistor separately.
Here is the images I get from the voltmeter:
Match up the voltmeter reading (A, B, C, or D) with the following: (+2) You might use one of the letters
more than once.
_____ 1. Voltmeter reading across the batteries
_____ 2. Voltmeter reading across the 5 Ohm resistor
_____ 3. Voltmeter reading across the 8 Ohm resistor
_____ 4. Voltmeter reading across the 6 Ohm resistor
_____ 5. Voltmeter reading across the 3 Ohm resistor
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Next problem: Each resistor is 10 Ohms and the total voltage of the batteries = 6V.
1. Find the Req.
Req = ________________________ Ohm
2. What is Ib?
Ib = _________________________ Amperes
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Next Problem…Each bulb has a resistance of 10 Ohms. Obtain theoretical ammeter readings and voltage
drops across each bulb.
Remember that to get power, we need to multiply the voltmeter reading (voltage drop) and the current (I)
through the device.
Find the power delivered by the battery: ___________________ W
Find the power used by bulb 1: _____________________ W
Find the power used by bulb 2: _____________________ W
Find the power used by bulb 3: _____________________ W
Find the power used by bulb 4: _____________________ W
Find the power used by bulb 5: _____________________ W
Find the power used by bulb 6: _____________________ W
Which bulb(s) of the six shines the brightest [note, may be more than one answer]?
Which bulb(s) of the six shines the dimmest [note, may be more than ozne answer]?
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Key to the problems:
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