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Unformatted text preview: 11/9/2011 16:26:00 a11/p11 Grading Scheme No. Scores Question A(1) Measure, tabulate, and plot the J vs. I curve. 1.5 pt. a. Proper data table marked with variables and units. 0.3 b. Proper sizes of scales, and units for abscissa and ordinate that bear relation to the accuracy and range of the experiment. 0.3 c. Proper data and adequate curve plotting (Fig. A1) 0.9 Question A(2) Estimate the maximum current I m with uncertainty in the linear region of the J vs. I curve. Mark the linear region on the J I curve figure by using arrows ( ) and determine the threshold current I th with uncertainty. 3.5 pts. a. Mark the linear region. 0.5 b. Leastsquare fit or eyeballing with ruler and error analysis 1.5 c. Obtain I m I m properly 0.5 d. Adequate value of I th I th 1.0 No. Sub scores Total scores B(1) Measure, tabulate, and plot the electrooptical switching curve ( J vs. V rms curve) of the NB 90 o TN LC, and find its switching slope , where is defined as (V 90 V 10 )/V 10 . 5.0 pts. a. Proper data table marked with variables and units. 0.3 b. Properly choose the size of scales and units for abscissa and ordinate that bears the relation to the accuracy and range of the experiment. 0.3 c. Correct measurement of the light intensity ( J ) as a function of the applied voltage (V rms ) and adequate J V rms curve plot. The intensity of the transmission light reaches zero value in the normally black mode. 0.4 There is a small optical bounce before the external applied voltage reaches the critical voltage. 0.8 The intensity of the transmission light increases rapidly and abruptly when the external applied voltage exceeds the critical voltage. 0.4 The intensity of the transmission light displays the plateau behavior as the external applied voltage exceeds 3.0 Volts. 0.4 d. Adequate value of with error, . Correctly analyzing the maximum light intensity. 0.6 Correctly analyzing the value of V 90 . 0.6 Correctly analyzing the value of V 10 . 0.6 Correct value, (0.42 ~ 0.44) 0.02. 0.6 B(2) Determine the critical voltage V c of this NB 90 o TN LC cell. Show explicitly with graph how you determine the value V c. 2.5 pts. 1 11/9/2011 16:26:00 a11/p11 Adequate value of V C with error, V C V C . Make the expanded scale plot and take more data points in the region of V C . 0.8 Correctly analyzing the value of V C . 0.7 Correct V C V C value, (1.2 ~ 1.5) 0.01 Volts. 1.0 C(1) Assume that the wavelength of laser light 650 nm, LC layer thickness 7.7 m, and approximate value of n 0.25 are known. From the experimental data T and T obtained above, calculate the accurate value of the phase retardation and accurate value of birefringence n of this LC cell at V=0....
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This note was uploaded on 11/08/2011 for the course PHYS 0000 taught by Professor Na during the Spring '11 term at Rensselaer Polytechnic Institute.
 Spring '11
 NA

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