Experiment: With the battery voltage set to 20 volts, measure the current in a parallel circuit with 1, 2, 3, and 4 light bulbs. (In each case, place the ammeter next to the battery.) Use Ohm’s law to calculate the total resistance of the circuit. Record results below.
Number of light bulbs
1
2
3
4
Voltage
20 volts
20 volts
20 volts
20 volts
Current:
Total resistance(show all work)
Number of light bulbs: 1
Current: 0.2 Amps
Total resistance:
R = V / I
R = 20 / 0.2
R = 100 ohms
Number of light bulbs: 2
Current: 0.13 Amps
Total resistance:
R = V / I
R = 20 / 0.13
R = 153.85 ohms
Number of light bulbs: 3
Current: 0.09 Amps
Total resistance:
R = V / I
R = 20 / 0.09
R = 222.22 ohms
Number of light bulbs: 4
Current: 0.07 Amps
Total resistance:
R = V / I
R = 20 / 0.07
R = 285.71 ohms