Radioactivity - PowerPoint PPT Presentation

Loading...

PPT – Radioactivity PowerPoint presentation | free to download - id: 81c53a-YWY0Y



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Radioactivity

Description:

Radioactivity Decay Constant Activity Exponential decay By Hannah I. Terhorst Decay Constant The decay constant of the radio-nuclide is the probability that an ... – PowerPoint PPT presentation

Number of Views:52
Avg rating:3.0/5.0
Slides: 13
Provided by: Terh152
Learn more at: http://www.dskl.edu.my
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Radioactivity


1
(No Transcript)
2
Radioactivity
  • Decay Constant
  • Activity
  • Exponential decay

By Hannah I. Terhorst
3
Decay Constant
  • ? decay constant
  • Exp.
  • 0.2 s-1 every nucleus has a 0.2 chance of
    decaying in one second
  • The decay constant ? of the radio-nuclide is the
    probability
  • that an individual nucleus will decay within a
    unit of time.

1
4
Activity
  • The activity A of a source is the number of its
    nuclei that decay in unit time.
  • Unit 1 becquerel (Bq) is an activity of 1 decay
    per second

2
5
Exponential decay
  • the number of nuclei in a sample always
    decreases in the same way
  • t ½ half time
  • different half-lives vary widely ? from seconds
    to millions of years
  • It is the time taken for half the radioactive
    nuclei to decay.

? Exponential decay curve
3
6
  • The higher the probability of decay ?
  • ? the more rapidly nuclide decay
  • ? the shorter is half-life

4
7
(No Transcript)
8
The age of rocks
  • Measuring how many 238U changed to 206Pb
  • Uranium-238 has a very long half-life of 4500
    million years ? stable nuclide lead-206
  • Other nuclides in the decay chain can be ignored

5
9
Carbon dating
  • Carbon-14 (14C) half-life of 5730 years
  • All living things take 14C more usual 12C
    (photosynthesis)
  • 14C slowly decays ? percentage slowly decreases
  • Used to date bones, wood, paper, cloths

6
10
Exp. Egyptian mummy
  • Step 1
  • Step 2

7
11
(No Transcript)
12
Source
  • Book page 342, 343, 345
About PowerShow.com