CHM 424 EXAM 2 - COVER PAGE FALL

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1 CHM 44 EXAM - COVER PAGE FALL 007 There are six umbered pages with five questios. Aswer the questios o the exam. Exams doe i ik are eligible for regrade, those doe i pecil will ot be regraded. coulomb charges amp coulomb per secod volt joule per coulomb ε C J - m - h J s k J K - c m s - amu kg i.54 cm N A mol - c v E hν ( l ) f Ri R out ( ) ( + ) dim + R M f d d d ob im ob ( )( ) ( )( ) * ( η ) +η σ * + + ( +η ) +ησ R si θ si θ mλ mλ tcosθ si θ m a dθ dλ m acos θ m dl dλ f dθ dλ hc λ mv +ω A 0.6λf ρ r log ( T ) R R TE TM si si ta ta ( θi θt) ( θ + θ ) i t ( θi θt) ( θ + θ ) i t taθ B siθ c λ Δ θ R λ mn Nacosθ m Δλ

2 CHM 44 EXAM FALL 007 Name Score /50 30 pts.. Provide the followig defiitios or facts at 6 pts each. a. Label six of the regios of the electromagetic spectrum b. List the types of trasitios that occur i each of the regios you labeled i (a) (i) (ii) (iii) (iv) (v) (vi) Exam, 007, page

3 c. A gratig moochromator is adjusted to pass 800 m light i the first order. What other wavelegths i the UV/visible regio will be passed? d. What is the most commo spectral source used to obtai ultraviolet (<350 m) absorptio spectra? e. What logic operatio is performed by the followig gates? (AND, OR, etc) Exam, 007, page

4 30 pts.. Perform the followig calculatios at 0 pts each. a. Cosider 300 m light. (4 pts) What is its frequecy i Hz? (4 pts) What is the eergy of oe photo i J? ( pts) What is its period i s? b. A 8-bit DAC has a output rage from 0 to +0 V. (i) Icludig zero, how may uique voltages ca be produced by the DAC? (ii) For the iput biary umber , what voltage is output by the DAC? c. A fluorometer is costructed with a xeo arc lamp havig a source size of 0. mm, a moochromator etrace slit width of mm, ad a source to slit distace of cm. What values of d ob, d im ad f (i cm) will magify the source to just fill the slit? (b) What optical property of the moochromator will determie the les diameter? Exam, 007, page 3

5 30 pts. 3. Aswer the followig two homework questios for 5 pts each. a. Write l(0) as a biary umber. Use six bits to the right of the biary poit. b. The silver iodide bod eergy is 55 kj/mol. What is the logest wavelegth of light that is capable of breakig the bod? Exam, 007, page 4

6 30 pts. 4. A sigal is sampled at khz by a aalog-to-digital coverter. The digitized data has two frequecies, 0 Hz (dc) ad khz. (a) A RC low pass filter with f 3dB khz is placed betwee the sigal source ad the aalog-to-digital coverter. The amplitude of the 0 Hz compoet drops to 0. its origial value, while that for the khz compoet drops to its origial value. What are the actual (ualiased) frequecies? (b) Based o your aswer to part (a), if the samplig frequecy is chaged to 6 khz what frequecies will be observed i the digitized data? Exam, 007, page 5

7 30 pts. 5. Suppose a optical compoet such as a les with refractive idex, 3, is surrouded by a material (such as air) havig a lower refractive idex,. I may istrumets the reflectio due to the refractive idex differeces caot be tolerated. It is possible to dramatically reduce the amout of reflectio by coatig the les with a itermediate refractive idex, < < 3. This is accomplished by makig the layer of material /4 λ thick. That is, if the light is at 600 m, the layer is made 50 m thick. The secod requiremet for a ati-reflectio (AR) coatig is to choose the value of so that R, R,3. What value of will accomplish this? (The aswer should give the value of as a fuctio of ad 3.) Hit: at oe poit i the derivatio it is prudet to take the square root of both sides of the equatio! Exam, 007, page 6

CHM 424 EXAM 2 - COVER PAGE FALL

CHM 424 EXAM 2 - COVER PAGE FALL CHM 44 EXAM - COVER PAGE FALL 006 There are seven numbered pages with five questions. Answer the questions on the exam. Exams done in ink are eligible for regrade, those done in pencil will not be regraded.