Download Slide 1

Your teacher will show you how to build this circuit.
Copy the table into your
book. Adjust the voltage
to each of the values
shown, and record the
current in the table.
Voltage
(V)
Current
(A)
0
0.00
0.1
0.25
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
6V
4.5
5.0
5.5
6.0
Now replace the bulb with a 22Ω resistor
Add another column to
your table to record the
current through the
resistor at the same
voltages.
22Ω
Voltage
(V)
Current
(A)
0
0.00
0.1
0.25
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
6V
4.5
5.0
5.5
6.0
1. Plot a graph of current against voltage for both components.
- plot both sets of data on the same graph
- use a sheet of A4 graph paper in a landscape orientation
- make sure current is on the y-axis and voltage is on the x-axis
2. Look at the values of current for both the bulb and resistor when the voltage
is 1V. Which component has the higher resistance at this applied voltage?
Explain your answer!!!
3. What happens to the resistance of the bulb as the voltage is increased?
Once again you must explain your answer.
4. At what voltage do the resistance of the bulb and the resistor become
equal? Explain how you were able to tell.
Your teacher will show you how to use Ohm’s Law to calculate the resistance
of the bulb at various points on the graph. Use this principle to answer
these questions:
1. What is the resistance of the bulb when:
a) The voltage is 2.5V
b) The voltage is 5V
c) The current is 0.15A
2. A bulb has a resistance of 12.5Ω. What current will flow through the bulb
when a voltage of 20V is applied?
4. Another bulb is rated as having a resistance 12Ω when the current is 0.6A.
What voltage is required to produce this current?