Question

# Circuit Construction

Choose one • 5 points

Go to this website to open the Circuit Construction

Simulator:

http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc

Choose the "Lab" option.

Check the "Values" box in the upper right hand corner of the screen.

Click and drag one battery, two resistors, and seven wires from the white box to the left of the screen.

Arrange the pieces into a circuit with the battery on top and the two resistors on the bottom:

Click on the battery and use the slider to change the voltage to 9.0 V.

Click on the left resistor and change the value to 10 Ohms.

Click on the right resistor and change the value to 20 Ohms.

Drag the ammeter from the toolbox on the right. Place the crosshairs of the ammeter on the wire (as pictured below) several places around the circuit to find the current in the wire. What is the current?

- 0.15 A
- 0.30 A
- 0.45 A
- 0.60 A

**QUESTION 2**

Circuit Construction

Choose one • 5 points

Is this circuit arranged in series, in parallel, or in both formations?

- Series
- Parallel
- Both series and parallel

**QUESTION 3**

Resistance

Choose one • 5 points

Based on your answer from #2, use one of the following equations to calculate the total resistance of the circuit.

**Resistance in Series**

R

t

o

t

a

l

=

R

1

+

R

2

**Resistance in Parallel**

1

R

t

o

t

a

l

=

1

R

1

+

1

R

2

- 6.67 Ohms
- 10 Ohms
- 20 Ohms
- 30 Ohms

**QUESTION 4**

Ohm's Law

Choose one • 5 points

Now, using Ohm's Law:

I

=

V

R

and the total resistance calculated in #3, what is the total current of this circuit?

- 0.15 A
- 0.30 A
- 0.45 A
- 0.60 A

**QUESTION 5**

Voltage

Choose one • 5 points

Drag the voltmeter from the toolbox on the right. A voltmeter measures the difference in the voltage between 2 places on a circuit. This is called the voltage drop. Place the contacts of the voltmeter on the circuit on either side of the battery (pictured below).

**Note: ***The voltmeter tells you the voltage drop between the two points in the circuit touched by the probes. *

*Voltage works in a similar fashion to gravitational potential energy based on height. Balls will only roll down board if one end is higher than the other (so it is sloped). The ball (electron) at the higher end of the board (wire) has lots of potential energy (voltage). The ball will roll down the board (electron will move through the wire) to the lower end of the board that has less gravitational potential (less voltage). You could use a ruler to measure the height difference between the high point of the board and the low point where the ball moves to. This would be the change in height or how hard the ball dropped in height. For the electron, you would use a voltmeter to measure how much the voltage dropped from one point to another. *

**What is the voltage drop across the battery?**

- -1.00 V
- -3.00 V
- -9.00 V
- -12.00 V

**QUESTION 6**

Voltage

Choose one • 5 points

Place the contacts on either side of the 10 Ohm resistor.

What is voltage drop across the 10 Ohm resistor?

- -3.00 V
- -4.50 V
- -6.00 V
- -9.00 V

**QUESTION 7**

Voltage

Choose one • 5 points

What is the voltage drop across the 20 Ohm resistor?

- -3.00 V
- -4.50 V
- -6.00 V
- -9.00 V

**QUESTION 8**

Voltage

Choose one • 5 points

Add together your answers from #6 and #7. Is this number greater than, less than, or equal to the voltage of our battery?

- Greater than
- Less than
- Equal to

**QUESTION 9**

Voltage

Choose one • 5 points

Change the voltage of the battery from 9 V to 15 V by Ctrl-clicking on the battery and selecting "Change voltage".

Use the voltmeter to remeasure the voltage across each of the resistors. Now how does the total voltage across the resistors compare to that of the battery?

**Note: **If you receive decimal points for any of your voltmeter readings, please round to the nearest whole number before adding and comparing.

- Greater than
- Less than
- Equal to

**QUESTION 10**

Circuit Construction

Choose one • 5 points

Change the battery's voltage back to 9 Volts, use three more wires, and rearrange your resistors so that the circuit is set up like this**:**

Is this circuit arranged in series, in parallel, or in both formations?

- Series
- Parallel
- Both Series and Parallel

**QUESTION 11**

Resistance

Choose one • 5 points

Based on your answer in #10, use one of the following equations to calculate the total resistance of the circuit:

**Resistance in Series**

R

t

o

t

a

l

=

R

1

+

R

2

**Resistance in Parallel**

1

R

t

o

t

a

l

=

1

R

1

+

1

R

2

- 6.67 Ohms
- 10 Ohms
- 20 Ohms
- 30 Ohms

**QUESTION 12**

Ohm's Law

Choose one • 5 points

Now, using Ohm's Law:

I

=

V

R

and the total resistance calculated in #11, what is the total current of this circuit?

- 1.35 A
- 0.90 A
- 0.45 A
- 0.30 A

**QUESTION 13**

Current

Choose one • 5 points

Using the ammeter, what is the current through the path with the 20 Ohm resistor?

- 1.35 A
- 0.90 A
- 0.45 A
- 0.30 A

**QUESTION 14**

Current

Choose one • 5 points

Again, using the ammeter, what is the current through the path with the 10 Ohm resistor?

- 1.35 A
- 0.90 A
- 0.45 A
- 0.30 A

**QUESTION 15**

Current

Choose one • 5 points

Add your answer for #13 and #14 together. What is significant about this number?

- This is equal to the total current you found in #12.
- This is less than the total current you found in #12.
- This is greater than the total current you found in #12.

**QUESTION 16**

Circuits

Choose one • 5 points

Use your observations of the circuit construction simulation experiment and your course notes to answer the following questions.

Which statement is true?

- When two resistors are connected in series, there is less total current in the circuit than if the two resistors were connected in parallel.
- When two resistors are connected in parallel, there is less total current in the circuit than if the two resistors were connected in series.
- The total current is the same regardless of if the two resistors are connected in series or in parallel.

**QUESTION 17**

Circuits

Choose one • 5 points

Which statement is true?

- Current varies throughout a series circuit.
- Current stays the same through a series circuit.

**QUESTION 18**

Circuits

Choose one • 5 points

Which statement is true?

- Voltage varies throughout a series circuit.
- Voltage remains the same throughout a series circuit.

**QUESTION 19**

Circuits

Choose one • 5 points

Which statement is true?

- Current varies throughout a parallel circuit.
- Current stays the same throughout a parallel circuit.

**QUESTION 20**

Circuits

Choose one • 5 points

Which statement is true?

- Voltage varies throughout a parallel circuit.
- Voltage remains the same throughout a parallel circuit.

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