7/25/2019 half life.pps

1/30

Author : Khairi

HALF LIFE CONCEPT

HALF LIFE

Time takenby radioactive substance for its :Activity of atoms

OR

OR

to decrease to half of its original value

T

!ass

"umber

7/25/2019 half life.pps

2/30

Author : Khairi

E#A!$LE

A radioactive decay for a radioactive sam%le

&' (anuary )''' *' (anuary )'''

Half life+T&,*- &' days

HALF LIFE CONCEPT

&'' g .' g

7/25/2019 half life.pps

3/30

Author : Khairi

Time /0'' %0m Time &*0'' %0m

Half life+T&,*- 1 hours

HALF LIFE CONCEPT

A radioactive decay for a radioactive sam%le

E#A!$LE

2'',minutes ).',minutes

7/25/2019 half life.pps

4/30

Author : Khairi

HALF LIFE CONCEPT

Half life of a radioactive sam%le is * days0!ass of theradioactive sam%le on &&th(anuary )''' is . g0

3hat 4as it mass on 2th(anuary )''' 5

E#A!$LE

&&th(anuary )''' 5 g

6th(anuary )''' 10 g

2th(anuary )''' 20 g

7/25/2019 half life.pps

5/30

Author : Khairi

HALF LIFE CONCEPT

Half life of a radioactive sam%le is * days0!ass of theradioactive sam%le on &&th(anuary )''' is . g0

3hat 4ill it mass on &.th(anuary )''' 5

E#A!$LE

&.th(anuary )''' 1.25 g

&)th(anuary )''' 2.5 g

&&th(anuary )''' 5 g

7/25/2019 half life.pps

6/30

Author : Khairi

A sam%le of radioactive has a half life of . days03hat is the activity of &''',s substance after &' days 5

&''' 0 day

.''

5 days

*.'

5 days

*.',s

HALF LIFE CONCEPT

E#ER7I8E

7/25/2019 half life.pps

7/30 Author : Khairi

9elo4 is a record of radioactive decay for a sam%lerecorded by a student

3hat is the half life of the radioactive sam%le 5

.''' )''' - *''' years

200 g

150 g

100 g

Year 3000

Year 4000

Year 5000

HALF LIFE CONCEPT

E#ER7I8E

7/25/2019 half life.pps

8/30 Author : Khairi

A radioactive sam%le has a half life of ) years0If mass of thesam%le is &' g03hat 4as the mass of the sam%le &. years ago 5

10 g no4

) years ago20 g

; years ago40 g

6 years ago80 g

&* years ago160 g

&. years ago)*' g

HALF LIFE CONCEPT

E#ER7I8E

7/25/2019 half life.pps

9/30 Author : Khairi

A sam%le of radioactive left *. < residual after . hours03hat is the half life of the sam%le 5

&''