From key@physics.utoronto.ca Wed Apr 2 09:16:50 2008 Date: Wed, 02 Apr 2008 09:16:49 -0400 From: Tony Key To: christina.yim@utoronto.ca, Tony Key Subject: Re: PHY138 Hi christina - Answers below. christina.yim@utoronto.ca wrote: > Hello Professor Key, > > I have several questions on the SN I and SN II materials. > > 1. In 1.5.B (worked example), the solution says that the line of 1890nm > does not appear in the photograph of the hydrogen spectrum. Why is that? > (is it something to do with the range of the hydrogen spectrum?) > Yes, our eyes are not sensitive to that range - which is in the infra-red. > 2. The graph shown on p.3 of Supplementary Notes II shows two spikes > caused by the characteristic X-rays. I was wondering, does K beta always > have the lower peak (meaning lower intensity) than K alpha? > That's a complicated question, depending on the atomic structure of the target and the cross-section for electron scattering in the target atom as a function of electron energy. (In fact, if you subtract the bremsstrahlung part of the spectrum under the two line spectra peaks, their intensity doesn't look too different!) Of course the ENERGY of the K-alpha is always less than that of the K beta, so the K beta has a shorter wavelenght. > 3. How does the increased voltage of an X-ray tube increase the > bremsstrahlung frequency? (lecture 3 powerpoint slide) > The increased voltage increases the energy of the electrons accelerated in the X-ray tube. In turn, they have more energy to give to the radiated photons. > Thanks in advance! You're welcome! TonyK > Christina > [ Part 2, Text/X-VCARD (charset: UTF-8 "Internet-standard ] [ Unicode") (Name: "key.vcf") 9 lines. ] [ Unable to print this part. ]