Question

Radioactive Decay

Objective: to study the radioactive decay of materials. Understand the  concept of half life and randomness of the radioactive decay

Run the case of H3 decay to He3:

• Go to “Multiple Atoms” tab
• Start with 80 atoms by clicking on the bucket.
• Start running and record the time when the number of H3 is changing to 40, 20, 10, and 5.This is accumulative time
• Repeat the above step 5 times and average them

(below is an example of table that you need to create):

Count	Time (trial 1)	Time (trial2)	Time (trial3)	Time (trial4)	Time (trial5)	Average time
40	12.4
20	27.3
10	39.5
5	55.6

• Using Excel plot count (y-axis) vs. average time (X-axis) (example below)
• Use exponential trend to fit the data, make sure the trend line equation is in the plot.

Find half life by following below steps:

1. Find the intersection of line to y axis (in your equation for x=0), in this example is 77.77 counts
2. Calculate half of the number from step 1 (in this case 77.77/2= 39)
3. Find the time that correspond to counts from step 2. You can draw a line in your plot by hand or use equation in the plot.
4. Record that value as a half life of the H3 decay.

Dear chegg, this is the questions you can help me to answer:

Answer the following questions for your report:

• What does half life means?
• Why your 5 trial numbers are different?
• What can you conclude from this experiment?

Answer 1

We have plotted H3 Average time T (year) vs count N graph and its linear trendline. The values represent the average time values and value represent the count values.

The linear trendline equation:

The slope of the trendline:

The -intercept or intersection of line to y axis of the trendline:

Therefore, the trendline equation is:

Half counts

The corresponding time for from the equation (1):

Therefore, the half life of H3 decay is 24.314 years.

What does half-life means?

It is the interval of time required for original sample radioactive nuclei to decay into one-half of the initial sample count. But it must be considered that it is not exactly means "half". It is the probability of a radioactive sample to decay in its 50% of original 100% within half-life.

Why your 5 trial numbers are different?

All five readings are slightly different because as explained above that half-life gives the probability of a radioactive sample count by that time of half-life. For example, we took 80 nuclei as an original count 100%, by the half-life it would be around 40. Now in the next stage, remaining 40 sample will decay to 20 by another half-life, so this goes on for many years.

What can you conclude from this experiment?

We can conclude that radioactive element decays into different elements, in our case H3 to H and those electrons participate to make He. We can also conclude that elements can have different half-life.