# Page 4

```Repeat the part Measurement
with the other two apertures (2mm and 8mm) including two new tables.
This is the end of Part A of the experiment.
You should now have 15 stopping potential values in 3 Tables.
Part B :
Refer to page 17 of the Pasco Instruction manual ‘PHOTOELECTRIC EFFECT APPARATUS’
Experiment 2 -Measuring Current-Voltage Characteristics 1
Measuring Current-Voltage Characteristics of Spectral Lines - Constant Frequency, Different Intensity
Preparation for Measurement
2, 3 and 4 have already been done if you did Part A of the experiment.
Do 5 - 8
Measurement – Constant Frequency, Different Intensities
2 mm Aperture
Do 1, 2
3. Adjust the – 4.5V to +30V VOLTAGE ADJUST knob until the current on the ammeter is zero.
Make table in you Lab Notebook :
l = 435.8nm
Current I/10-11 A
2mm
l = 435.8nm
Voltage U/V
4mm
l = 435.8nm
8mm
0
0
Current I/10-11 A
Voltage U/V
0
Current I/10-11 A
Voltage U/V
0
0
0
Record the voltage and current in the table
The voltage will be negative – this is the stopping potential (example -1.569 V)
4. Increase the voltage to zero (U = 0V).
Record the new voltage and current in your table
Repeat the part :
Measurement – Constant Frequency, Different Intensities
2 mm Aperture
with the 4 mm Aperture and
with the 8 mm Aperture
Repeat the part :
Measurement – Constant Frequency, Different Intensities
2 mm Aperture, 4 mm Aperture , 8 mm Aperture
with the 546.1 nm filter
Make a new table.
This is the end of the experiment.
You should now have for Part B : 2 tables (2 times 3 values for I). The values for V are not used.
Turn off the MERCURY LAMP power switch and the POWER switch on the other pieces of equipment.
Cover the windows of the Mercury Light source Enclosure and the Photodiode Enclosure.
Tell you instructor that you finished the Lab.
B4
```