Measuring Radioactivity - Video Tutorials & Practice Problems
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1
concept
Units of Radiation Measurement
Video duration:
2m
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Here we're going to say that radiation can be measured in several different ways depending on which property is being measured. So here we're gonna have units of radiation measurement, and what we need to realize is that there are a lot of common units used for radiation. We have curie, we have, road engine, we have rads, and we have REM. Alright. So let's start out with our curies. We're going to say here that 1 curie is equal to 3.7 times 10 to the 10 disintegrations per second. And we're going to say that the SI unit is 1 Beck quarrel, which is b q. So I'm gonna butcher some of these because the names are a little bit different than what we're used to seeing. So we're gonna say that 1 b q is equal to 1 disintegrations per second. And we're going to say here, what property is it measuring? We're gonna say that it's measuring decaying events or decay events. Next, we have one Roedinger, which is r capital r. We're gonna say that 1 Roedinger is equal to 2.1 times 10 to the 9 charges per centimeters cubed. Here we don't have an s I unit equivalent to it, and we need to realize here it deals with the exposure in terms of ionizing intensity of gamma and x rays. Next, we're going to say we have rads. So we're gonna say here 1 rad is equal to 1 times 10 to the negative 5 joules over grams, and that 1 rad is equal to 1 capital r. So it's equal to 1 rotogen. Alright. Next, we're going to say the SI unit equivalent of that is gray or g y. We're gonna say here that 1 gray is equal to 1 joule over kilograms, and it's also equal to 1 rad. So you can start seeing that some of these units are connected to one another. This will allow us later on to convert from one radiation unit to another. Now here, this is deals with energy absorbed by tissue. Then we have rem, r e m. Rems equals rad times r b e. R b e is your relative biological effectiveness. We're gonna say the SI unit of that is our Sivert or SV. One Sivert is equal to 100 REM. And then we're gonna say what exactly, is the property measuring? It's measuring tissue damage. Now finally coming back to r b, e, which is your relative biological effectiveness, it factors account for both your ionizing intensity and biological effect. And we're gonna say here that x rays, we're gonna say here gamma rays, we're gonna say here beta particles, their r b e is equal to 1. And when it comes to alpha particles which are larger, their r b e is equal to 20. So here these are the most important types of radiation units that you should keep in mind. Realize only the ones that are in purple, remember our purple boxes, are the ones that are important in terms of memorization. The others would be given to you in some way either in a formula sheet or within the question itself.
2
example
Measuring Radioactivity Example
Video duration:
33s
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The initial responders of Chernobyl nuclear disaster were exposed to 23 s v's of radiation. Convert this value to REM. Alright. So all we got to do here is use the conversion factor, and realize 23 s v, the conversion factor is that for every one s v we have 100 r e m's. So when we do that, s v's cancel out and we'll go off with r e m at the end. This comes out to 23100 r e m as the new units for our radiation.
3
Problem
Problem
A typical chest X-ray exposes a patient to an effective dose of 0.09 mSv. How many Rad is this?
A
25 rad
B
0.125 rad
C
0.009 rad
D
37 rad
4
Problem
Problem
Two technicians in a nuclear laboratory were accidentally exposed to radiation. If one was exposed to 5 mGy and the other to 9 rad, which technician received more radiation?
A
The one exposed to 5 mGy
B
The one exposed to 9 rad
C
The two technicians were exposed to the same amount of radiation
5
Problem
Problem
A solution of iodine-131, a radioisotope used in the diagnosis and treatment of thyroid disease, is found just prior to administration to have an activity of 1.08 x 106 Bq/mL. If 2.57 mL were delivered intravenously to the patient, what dose of I-131 ( in µCi) did the patient receive?
A
7.50×10–5 µCi
B
75.0 µCi
C
29.2 µCi
D
0.075 µCi
E
0.029 µCi
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