From key@physics.utoronto.ca Mon Mar 31 21:37:08 2008
Date: Mon, 31 Mar 2008 21:36:58 -0400
From: Tony Key <key@physics.utoronto.ca>
To: kueiyu.lee@utoronto.ca
Subject: Re: physic 138 student

Great question, Kate, took me 10 mins to figure out. 0.95 is the density of
tissue as given in the table in SNIV  - rho_c is the cancer density, rho_t
is the tissue density.  The latter is 1*0.95 and the density of the cancer
is 20% higher, i.e. 1.2*0.95.

Whew!  I thought I had lost another $5.

Let me know if this makes sense to you.

TonyK

kueiyu.lee@utoronto.ca wrote:
> Hello Professor Key,
>
> My name is Kate. I am a physics 138 student. I am sorry to bother you but
> I was wondering if you could help me with one of the worked examples
> posted on the website. It's about problem 2.5(ii) Resolution of X-rays.
>
> I understand what you did in the middles steps, I just don't get why you
> multiply by 0.95 for the very last step.
>
> Thank you so much for your time and help. It's greatly appreciated.
>