# Half life Results- Protactinium-234 and Indium-116

Here are the results from the Protactinium Generator Experiment. Your task is to correct for background (take the background count per second away from the count rate) and then plot a graph of count rate (cps) against time (s). Remember the count rate was taken every 10 s but shows the value of the count rate (for one second)

Background count rate (c.p.m.) 48.0,   46.0,   42.0

Average background count rate (c.p.m.)    45.3

Average background per second (c.p.s.)    work it out!

TimeCount rate
(s)(cps)
080.3
1073.9
2067.3
3060.5
4055.2
5049.6
6045.7
7041.5
8037.4
9034.1
10031.3
11028.5
12025.9
13023.9
14021.7
15019.4
16017.6
17016
18014.9
19013.4
20012.3
21011.2
22010.2
2309.2
2408.4
2507.5
2606.9
2706.4
2805.7
2905.3
3004.7

##### Indium 116 Half Life

Here are the results for the Indium-116 half life experiment. Warning, do not plot a graph in 15 minute intervals or you will have more difficulty finding the half life. Make the scale ten minute intervals.

You can track the experiment yourself through the link below

Indium-116 files

Background count = 31 c.p.m.

Time Time from startCount rate
(hours)(mins)(c.p.s.)
9:000675
9:1515570
9:3030452
9:4545375
10:0060328
10:1575275
10:3090219
10:45105181
11:00120164
11:15135149
11:30150126
11:45165106
12:0018090

Here are three more examples for you to practice producing a half life graph and for finding the half life of Protactinium

##### Example 1:

Background Count (cps):    5,   5,   3,  5,   4,   5,   5.

Time (s)Count in 10s
0308
10279
20240
30217
40197
50182
60165
70158
80145
90129
100116
110109
12098
13089
14080
15075
16066
17060
18055
19050
20046
21043
22035
##### Example 2:

Background Count (cps):     4,       3,      5.

Time (s)Count in 10s
0841
10752
20693
30622
40593
50544
60481
70443
80392
90364
100341
110301
120272
130251
140243
150211
160204
170183
180172
##### Example 3:
time
(s)
Count
in 10s
corrected
count
in 10s
Corrected
Count
Rate
(cps)
Background
count
(cp10s)
0
5105100.510.055
209590.59.055
358176.57.653
509085.58.555
658681.58.154.5
807368.56.85
957671.57.15
1107974.57.45
1255348.54.85
1405348.54.85
1555853.55.35
1706156.55.65
1856055.55.55
2004338.53.85
2156055.55.55
2304843.54.35
2454540.54.05
2604439.53.95
2754237.53.75
2904742.54.25
3052823.52.35
3203126.52.65
3353631.53.15
3503227.52.75
3652419.51.95

You should now have had plenty of practice at finding the half life graphically, nothing should phase you now.

## Author: Mrs Physics

Hopefully a one stop shop for all of your National 5 Physics Requirements