ACTIVITY – DC VIRTUAL LAB SOFTWARE 2

 

DESCRIPTION


The University of Colorado has created many interactive online tools related to science.  One of them is called the Circuit Construction Kit – DC Virtual Lab.  It allows you to build simple circuits inside an interactive online tool.

 

LINK

 

https://phet.colorado.edu/sims/html/circuit-construction-kit-dc-virtual-lab/latest/circuit-construction-kit-dc-virtual-lab_en.html

 

INSTRUCTIONS

 

NOTE: You should have completed the first activity with this software before doing this activity.

 

CIRCUIT 1 - SERIES

A series circuit that consists of a 10V battery, a 40 ohm resistor R1 and a 60 ohm resistor R2.


 

CIRCUIT INSTRUCTIONS


Create the circuit described above and answer the questions below:

 

A)    Use an ammeter to determine the current in the circuit.  Write your answer down.

B)     Add another ammeter elsewhere in the circuit.  Is the current the same or different?  Write your answer down.

C)     Using the battery’s voltage and the measured current, use Ohm’s Law to determine the resistance in the circuit.  Write your answer down.

D)    Analyze the circuit to see if your answer from B seems to make sense with your understanding of resistance in series circuits.  Write your answer down.

E)     Use a voltmeter to determine the V1 (voltage drop over the 40 ohm resistor R1).  Write your answer down.

F)     Use a voltmeter to determine the V2 (voltage drop over the 60 ohm resistor R2).  Write your answer down.

G)    How do your answers in D and E compare to the voltage of the battery?  Write your answer down.

CIRCUIT 2 – PARALLEL


A parallel circuit that consists of a 10V battery and two 50 ohm resistors.

 

 

CIRCUIT INSTRUCTIONS

H)    Use a voltmeter to determine the voltage drop over each resistor.  Write your answer down.

I)       Try changing the resistances to different values.  Does the voltage drop change?  Write you answer down.  Return the resistances to 50 ohms.

J)      Use an ammeter near the battery to determine the current leaving the battery.  Write your answer down.

K)     With the voltage of the battery and the current reading from the previous step, use Ohm’s Law to calculate the total resistance for the circuit.  Write your answer down.

L)     Consider the circuit and the total resistance you calculated in the previous step.  Does the value match with your understanding of resistance in parallel circuits?  Write your answer down.

M)   Now setup two more ammeters – one in each branch.  What is the current in each branch?  Write your answer down.

N)    Change the resistances.  Try 70 ohms and 30 ohms.  How does the current change?  Write your answer down.

Notice that there is a ratio that is the same but opposite of the resistances.  So if one branch has 70% of the resistance and the other has 30%, then their current amounts will be 30% and 70%.

 

CIRCUIT 3 – COMBINATION


Create the combination circuit below.  Let R1 be the 100 ohm resistor, R2 the 80 ohm resistor and R3 be the 70 ohm resistor.

 

CIRCUIT INSTRUCTIONS

 

O)    Use an ammeter to determine the current leaving the battery.  Write your answer down.

P)     With the battery’s voltage and your current reading from the previous step, use Ohm’s Law to determine the total resistance in the circuit.  Write you answer down.

Q)    Now calculate the total resistance using resistance equations.  First, calculate the resistance in the parallel section.  Then, calculate the total resistance in the circuit.  Write your answer down.

R)     Do your values of resistance in P and Q match?  Write your answer down.

S)     Use a voltmeter on each resistor to determine their voltage drop.  Write your answers down.

T)     What relationship (equation) can you see between the total voltage and R1 and R3?  Write your answer down.

U)    What relationship can you see between the VT and R2 and R3?  Write your answer down.

 

Save your work to share with your teacher.  You will get instructions on how to submit.