physics halflife

Watch this thread
izzi_xox
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 4 years ago
#1
if i was asked what the definition of half-life is, would I say it is the time taken for the number of nuclei in a sample to halve, or would I say it is the time taken for the count rate/activity in a sample to halve from its initial rate?
0
reply
chinua achebe
Badges: 8
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 4 years ago
#2
either:
-average time taken for a substance to decrease by half in terms of activity
or
-average time take for half of the radioactive atoms to decay
0
reply
username3626988
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report 4 years ago
#3
it can be either:

avg time it takes for number of nuclei of isotope in a sample to halve
OR
avg time it takes for count rate from sample containing isotope to fall to half of its initial level
0
reply
Backwad
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 4 years ago
#4
No just say

Half life is the term given to describe the amount of time (on average) it takes for the number of unstable nuclei in a radioactive sample to half

Radiation dose: a measure of the risk of harm

Affected by which organs radiation is exposed to
What type of radiation you’re exposed to
Amount of radiation your exposed to
Existing health problems eg skin issues Tukka akhi
0
reply
triga12345
Badges: 7
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
Report 4 years ago
#5
(Original post by chinua achebe)
either:
-average time taken for a substance to decrease by half in terms of activity
or
-average time take for half of the radioactive atoms to decay
^^
0
reply
Backwad
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report 4 years ago
#6
(Original post by triga12345)
^^
What do u think the grade boundaries will be
0
reply
RainDancess
Badges: 8
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Report 4 years ago
#7
40-5
38-6
50-7
62-8
78-9
just my opinion
0
reply
triga12345
Badges: 7
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report 4 years ago
#8
(Original post by RainDancess)
40-5
*38-6*
50-7
um what? im going to assume you meant 48-6 but do you really think 6-7 will be split by 2marks/?

9-?
8-71
7-63
6-56
5-49
4-41
0
reply
RainDancess
Badges: 8
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#9
Report 4 years ago
#9
(Original post by triga12345)
um what? im going to assume you meant 48-6 but do you really think 6-7 will be split by 2marks/?

9-?
8-71
7-63
6-56
5-49
4-41
no point in trying to guess lol, it wont be 90% for a 9 like some people say on here tho i reakon it wont be much more than 50 for a 7
0
reply
LarissaAlves
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#10
Report 4 years ago
#10
this is from BBC bitesize


The nuclei of radioactive atoms are unstable. They break down and change into a completely different type of atom. This is called radioactive decay. For example, carbon-14 decays to nitrogen-14 when it emits beta radiation.
It is not possible to predict when an individual atom might decay. But it is possible to measure how long it takes for half the nuclei of a piece of radioactive material to decay. This is called the half-life of the radioactive isotope.
Two definitions

There are two definitions of half-life, but they mean essentially the same thing:
  1. the time it takes for the number of nuclei of the isotope in a sample to halve
  2. the time it takes for the count rate from a sample containing the isotope to fall to half its starting level

Different radioactive isotopes have different half-lives. For example, the half-life of carbon-14 is 5,715 years, but the half-life of francium-223 is just 20 minutes.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest

How did The Student Room help you with your university application?

Talking to current university students (2)
20%
Talking to peers going through the same thing (1)
10%
Speaking to student ambassadors from the universities (0)
0%
Speaking to staff members from universities (0)
0%
Using the personal statement builder, library or helper service (2)
20%
Reading articles about what steps to take (4)
40%
Learning about/speaking to Student Finance England (0)
0%
Something else (tell us in the thread) (1)
10%

Watched Threads

View All