From key@physics.utoronto.ca Fri Mar  7 14:57:57 2008
Date: Fri, 07 Mar 2008 14:57:56 -0500
From: Tony Key <key@physics.utoronto.ca>
To: karen.peralta@utoronto.ca
Subject: Re: PROBLEM SET NUMBER 2

Hi Karen - Thanks for your question.  I'm not sure which problem you are
haing difficulty with.

However, here are some suggestions based on your question.

The definition of energy fluence rate - remember the strong recommendation
for definitions I made in class!? - is the number of photons of radiation
crossing one square metre per second.  In fact the  first problem in PS2 is
almost exactly the same as the one I did in class.  Look at the journal
notes for last lecture.

In the second problem, the exposure rate is given - it is the number of
Roentgens per unit time - here R/hr.  Commonsense would suggest that this
rate is directly proportional to the number of electrons hitting the X-ray
tube target per second, which, in turn, is just proportional to  the current
in the tube.

We'd also expect that the intensity of the X-rays falls off with distance in
a similar fashion, as, e.g. the intensity of light falls off with distance
from the light bulb.  If you can't make a good guess for that dependency,
open the hint.

Let me know if that helps.  If you have more questions, try and make them
more specific so I know which problem we are dealing with!

TonyK

karen.peralta@utoronto.ca wrote:
> Hello professor Key
> 
> I'm Having some trouble in this problem set, I don't know which  formula
> to use in order to find the exposure rate and the energy  fluency rate I'm
> very confuse for this problem set and I don't know  how to approach it do
> you have any tips for me thanks
> 
> Karen
> 

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