http://jersey.uoregon.edu/vlab/Voltage/
Some important information:
Voltage =
Volts =
The problem consists of two parts:
The
formula for OHM’S LAW part will be
discovered through a trial-and-error experiment:
1)
You are given a circuit on which you may vary the voltage by :
a) choosing from a variety of batteries
b) changing the resistance by adding
resistors to the
circuit.
2)
You will then turn on the switch, allowing current to flow through the circuit.
a) If the resistance is too low, the
lightbulb will receive too much current,
and will explode.
b) If the resistance is too great,
the lightbulb will not receive enough current, and will not
light.
c) If the resistance is just right, the
lightbulb will light up.
(Note:
real light bulbs are not perfect ohmic resistors as is the case here
and
will light partially with any amount of current).
3) If the lightbulb explodes or fails to light,
turn off the switch (which automatically
replaces the lightbulb) and try again.
Voltage Circuit Simulator P.
2
The
strategy:
1.
First, concentrate on changing the resistance to get the lightbulb to
turn on.
3. Once you get a working circuit write down
your values in the table below:
Trial # |
Voltage (V) |
Resistance (R) |
Amperage (I) |
1 |
6
V |
|
2 |
2 |
12
V |
|
2 |
3 |
18
V |
|
2 |
4 |
24
V |
|
2 |
4. Change the value of the battery, and try
again.
5. Q: What do you predict would be the resistance necessary to light
the bulb if the voltage was 36 V?
6. Q: Write a statement
that describes how the resistance changes as the voltage is changed but the
amperage remains constant.
7. Q: Look carefully at
the completed data table. Write a statement
that explains how the voltage and resistance can be used to determine the amperage
8. This relationship
is called Ohm’s law. Which of these
statements is the correct mathematical equation for this law?
a) I = VR b) I = V/R c) I = R/V
Use this circuit: http://jersey.uoregon.edu/vlab/Voltage/volt1.html
to complete the following table:
Volts (V) |
18 |
36 |
54 |
72 |
Amps (I) |
3 |
3 |
3 |
3 |
Resistance (R) |
|
|
|
|
9.
Which statement correctly identifies this relationship?
a) R = IR b) R= V/I c) R = I/V