Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

/ibiscm mod/ibis/v iew.php?id 2875983 sapling learning.com O 0/25/2016 11:55 PM

ID: 803764 • Letter: #

Question

/ibiscm mod/ibis/v iew.php?id 2875983 sapling learning.com O 0/25/2016 11:55 PM A 80.8/100 G 05:36 PM 10/20/2016 Gradebook Attempts Score tr Print Calculator Periodic Table Question 8 of 17 Map EA Sapling Learning A sample of an unknown isotope decays according to the figure. What is the half-life? Number E 100 years E 20 0 5000 10,000 15,000 20.000 Time (Years) O Previous 2 check Answer Next Exit D 2011-2016 Sapling Learning, Inc. 32 about us careers partners Privacy policy terms of use contact us help 1 NT 02 P Assignment Information Available From: 0/13/2016 06:00 PM 10/25/2016 11:55 PM Due Date: Points Possible Grade Category: Graded Description: Policies ODU 10 You can check your answers. You can view solutions after the due d You have three attempts per question. You lose 10% of the points available to each answer in your question for each incorrect attempt at that answer. For multiple choice questions, the penalty depends on the number of choices available. O eTextbook O Help With This Topic O Web Help & Videos O Technical Support and Bug Reports Y 6:53 PM 10/20/2016

Explanation / Answer

To calculate the half time of the given decay with ion the given time.The following steps are taken they are :

1) First at the zero days the percent of the unknown elements value is taken .Here the value is 100 which is on the Y-axis.

2)For the half life calculation the Y- axis value is divided by 2 ie it should be half.

hence 100/ 2 = 50

3)Then the 50 point is taken on the Y-axis.A horizontal line is drawn from the 50 on the graph.It meets the line at some point.

4) Draw the vertical line from that point to the X - axis.

5) Now it meets at a point 400 on the X - axis.

This will be the first half life of the given data. ie 400 years.

6)Now again the 500 value is divided by 2 then the value is 50/2 = 25 on the Y - axis.

7) Now same from the 250 value horizontal line is drawn to the graph.

8)It meets at some point and from that meeting point draw vertical line to the X - axis.

It meets at a point 90,000 on the graph.

Hence the second half life is 90,000 years

Now the half life is calulated as t1/2 = 9,000 - 400 = 8600 years.

9) Now again the Yaxis value 25 is halfed then 12.5.

10) from the 12.5 on the Y - axis a horizontal line is drawn

11)From the meeting point on the graph vertical line is drawn to the X - axis.

It meets at the point on the X - axis is 14,000 years

Now the 2nd half life is calculated as 9000 - 14000 = 5000years

Now the total half life is calculated as 1st half life + 2nd half life.

8600+5000 = 13,600 years.