Half life

Question 1

Radioactive substances give out radiation from nuclei of atom no matter what

How is this radiation measured ?

Answer 1

Geiger muller tube and counter which records count rate and number of radiation counts reaching it per sec

Question 2

Radioactive decay is a ———- process

Answer 2

random
You cannot predict when the nucleus in sample will decay

Question 3

What can half life be used for ?

Answer 3

make predictions about radioactive sources although decay is a random process

find the rate at which source decay = activity
measured in becquerels Bq ( 1 Bq per sec )

Question 4

define half life

Answer 4

time taken for the number of nuclei of isotopes in a sample to halve

or time taken for count rate from a sample containing isotopes to fall to half its initial level

Question 5

radioactive nucleus decay to become stable nucleus

Answer 5

the activity as a whole decreases
for some isotopes it takes a few hours for nearly all the number of unstable nuclei to decay whilst for others it takes years

Question 6

The problem with trying to measure the activity

Answer 6

the activity never reaches zero to measure how quickly activity drops off

EXAMPLE PG 198

Question 7

https://www.youtube.com/watch?v=wj9BzGFao8k

Answer 7

https://www.youtube.com/watch?v=zXw2cOSBB8E