PASCO Specialty & Mfg. SE-9639 User Manual download pdf (Page 18)

SE-9639 Franck-Hertz Experiment

012-14264A

• Diff between Peaks = diff(1,[Trough Voltage (V)]) with units of (V)

(This calculation calculates the voltage difference between adjacent current troughs.)

9. In the table, turn on the mean and standard deviation.

Recording Data

1. Make sure the accelerating voltage V

G2K

is zero.

2. After the filament has warmed up for about 15 minutes, click Record and slowly increase the accelerating voltage (take

about two minutes). Do not exceed 85 V.

CAUTION: While you are increasing the voltage, if you see the current suddenly increase, immediately

return the voltage to zero and decrease the filament voltage slightly, Wait for a few minutes for it to cool,

and repeat the recording.

Analysis

1. Using the coordinates tool on the graph, find the voltage of each of the peaks and troughs and record them in the table in

the Peak Voltage and Trough Voltage columns respectively.

2. The voltage differences between adjacent peaks and the voltage differences between adjacent troughs will be calculated

automatically in the table. Record the mean and standard deviations for the differences. The standard deviations give

the uncertainties in the difference measurements.

3. Use the mean voltage difference (V

) to calculate the value of Planck's Constant, h:

where e = 1.602 x 10

-19

C,  = 108.1 nm and c = 3 x 10

m/s. The answer will be in J•s.

4. Calculate the percent difference between the experimental value and the accepted value (h

= 6.626 x 10

-34

J•s).

5. Estimate the uncertainty in the experimental value of Planck's Constant using the uncertainty in the voltage difference.

he

------





1 2 ... 13 14 15 16 17 18 19 20 21 22 23 24 25

No comments

PASCO Specialty & Mfg. SE-9639 User Manual Page 18