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APhO 2001, Експеримент — Задача 4. Question (4)

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Всички материали от APhO 2001

2nd Asian Physics Olympiad — TAIPEI, TAIWAN — Experimental Competition — Thursday, April 26, 2001 · 26 април 2001 г. · 4 т.

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Time Available : 5 hours

Read This First:

Use only the pen provided.
Use only the front side of the answer sheets and paper.
In your answers please use as little text as possible ; express yourself primarily in equations, numbers and figures. If the required result is a numerical number, underline your final result with a wavy line.
Write on the blank sheets of paper the results of all your measurements and whatever else you consider is required for the solution of the question and that you wish to be marked.
It is absolutely essential that you enter in the boxes at the top of each sheet of paper used your Country and your student number (Student No.). In addition, on the blank sheets of paper used for each question, you should enter the number of the question (Question No.), the Section label, the progressive number of each sheet (Page No.) and the total number of blank sheets that you have used and wish to be marked for each question (Total No. of pages). If you use some blank sheets of paper for notes that you do not wish to be marked, put a large cross through the whole sheet and do not include them in your numbering.
At the end of the exam please put your answer sheets and graphs in order.

Условие

Find effects of irradiance.

a. Measure and plot the $I_{sc}$ vs. relative light intensity curve, and determine the approximate functional relationship between $I_{sc}$ and the relative light intensity.

b. Measure and plot the $V_{oc}$ vs. relative light intensity curve, and determine the approximate functional relationship between $V_{oc}$ and the relative light intensity.

Отговори

Решение

(4) (Question (4) : 4 points)

Find effects of irradiance.

a. Measure and plot the $I_{sc}$ vs. relative light intensity curve, and determine the approximate functional relationship between $I_{sc}$ and the relative light intensity.

( $\mathcal{I}_0$ is the light intensity when the axes of the two polarizers are parallel)

Graph of Isc (mA, 0–0.6) versus τ/τ0 (0–1): the points lie on a straight line through the origin up to about 0.58 mA at τ/τ0 = 1.

⊙Correct usage of polarizers and filters to change the illumination light intensity (1 point)

(Because polarizers are less effective for light with wavelength shorter than that of yellow light as mentioned in the description of “Equipments and Materials”, in order to obtain correct relative scale of irradiance, the yellow filter should be used with polarizers)

⊙Correct measurement of $I_{sc}$ and determination of the relationship between $I_{sc}$ and light intensity, including proper plotting of the relationship and knowing how to apply Malus’s law. (1.5 points)

( $I_{sc}$ is approximately proportional to light intensity: $I_{sc} = A\ \mathcal{I}/\mathcal{I}_0$ )

b. Measure and plot the $V_{oc}$ vs. relative light intensity curve, and determine the approximate functional relationship between $V_{oc}$ and the relative light intensity.

$\mathcal{I}/\mathcal{I}_0$	$I_{sc}$ (mA)	$V_{oc}$ (volts)
1	×××	×××
0.93
0.75
0.50
0.25
0.067
0.00

Graph of Voc (volts, 1–2.5) versus τ/τ0 (0–1): Voc jumps from about 1.1 V at 0 to 2.1 V at 0.067 and then rises slowly to about 2.45 V at 1; inset: Voc (volts, 2.1–2.5) versus Ln(τ/τ0) from −3 to 0, a straight line.

⊙Correct measurement of $V_{oc}$ and determination of the relationship between $V_{oc}$ and light intensity including proper plotting of the relationship. (1.5 points)

( $V_{oc} = A\,\ell n\,(\mathcal{I}/\mathcal{I}_0) + B$ or $V_{oc} = A'\log(\mathcal{I}/\mathcal{I}_0) + B'$ )

Оригинал в Архива: exp.pdf · официални решения: exp_sol.pdf