Collect data: Measure the current in the circuit using the resistor and voltage combinations given below.
Voltage
10 volts
20 volts
30 volts
Resistance
20 ohms
20 ohms
30 ohms
Current:
Voltage
30 volts
30 volts
30 volts
Resistance
20 ohms
100 ohms
200 ohms
Current:
Observe: Turn the light switch On to start the flow of current. An ammeter is a device that measures current in Amperes (A). Drag the Ammeter () to various parts of the circuit.
Is the current the same throughout, or does it change?
The same.
What is the current in the wire now?
Apply: The light bulb is also a resistor. Place the light bulb in the circuit, then use Ohm’s law to find the resistance of the light bulb. What is it?
To find the resistance of the light bulb, we can use Ohm's law:
Resistance (R) = Voltage (V) / Current (I)
If the voltage across the light bulb is 30 volts and the current flowing through it is 0.15 A (as calculated below), then the resistance of the light bulb can be found as follows:
Resistance = 30 volts / 0.15 A = 200 ohms
Therefore, the resistance of the light bulb is 200 ohms.
To find the current flowing through the light bulb, we can use Ohm's law again:
Current (I) = Voltage (V) / Resistance (R)
Current = 30 volts / 200 ohms = 0.15 A
So, the current flowing through the light bulb is 0.15 Amperes.