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Detector Building C
BirdSO 2022 Mini
December 11th-18th, 2021
Directions:
- Work is not required on calculation questions, but partial credit will be given for work shown if the final answer is incorrect.
- Significant figures will not be checked. Ensure that your answers have enough precision to be distinguishable.
Use the following symbol representing a circuit element for the next 3 questions.
- (2 points) What circuit element is this? A. Resistor B. Zener Diode C. Transistor D. Incandescent Light E. Light Emitting Diode F. Any source of light
- (3 points) Which of the following are true of the point represented by the left side of the diagram? ⃝ It should be connected to positive voltage. ⃝ Connecting it to positive voltage will damage the component. ⃝ It corresponds to the flat spot on the component. ⃝ It corresponds to the longer leg of the component. ⃝ It represents the direction that light is emitted in. ⃝ It is known as the cathode.
- (3 points) Which of the following are true of the point represented by the right side of the diagram? ⃝ It should be connected to positive voltage. ⃝ Connecting it to positive voltage will damage the component. ⃝ It corresponds to the flat spot on the component. ⃝ It corresponds to the longer leg of the component. ⃝ It represents the direction that light is emitted in. ⃝ It is known as the cathode.
- (2 points) Two identical resistors are placed in series with a current source. The voltage drop across the pair of resistors is 5 V. What would the voltage across each resistor be if they were placed in parallel with the current source instead? A. 1.25 V B. 2.50 V C. 3.75 V D. 5.00 V E. 7.50 V F. 10.00 V
- (2 points) What color of light corresponds to a wavelength of 656.28 nm? A. Infrared B. Red C. Green
B. 4. 3 Ω
C. 5. 5 Ω
D. 8. 8 Ω
E. 10 Ω
F. 41 Ω
- (2 points) If the network is connected to a 22 V source, what will be the voltage across the 6 Ω resistor? A. 1 V B. 2 V C. 6 V D. 12 V E. 22 V F. 44 V
- (2 points) If the network is connected to a 110 V source, what will be the current through the 10 Ω resistor? A. 3 A B. 6 A C. 10 A D. 11 A E. 22 A F. 55 A
- (2 points) If the network is connected to a 1 A source, what will be the power dissipated by the 5 Ω between points b and d? A. 0.75 W B. 1.00 W C. 1.25 W D. 2.00 W E. 2.50 W F. 5.00 W
- (2 points) A conductivity meter measure the concentration of a solution of NaCl as 100 ppm. However, the conductivity meter was calibrated at a temperature of 298.15 K while the solution was at a temperature of
- 15 K. What is the true concentration of the solution? A. 92 ppm B. 96 ppm C. 100 ppm D. 104 ppm E. 108 ppm F. 112 ppm
- (3 points) Which of the following semiconductors can be used to construct both red and green LEDs? ⃝ Zinc selenide ⃝ Gallium phosphide
⃝ Gallium arsenide phosphide ⃝ Aluminium gallium indium phosphide ⃝ Gallium arsenide ⃝ Aluminium gallium phosphide
- (2 points) An ideal LED has a forward voltage of 2.718 V. What is the wavelength of light emitted by the LED? A. 656 nm B. 575 nm C. 532 nm D. 478 nm E. 456 nm F. 403 nm
- (2 points) Which of the following is an accurate description of the luminous efficacy of an LED? A. It is the ratio of the power used by an LED to the wavelength of light emitted. B. It is a measure of how pure the spectrum of light emitted by the LED is. C. It is the ratio of the power used by the LED to the power emitted in the form of visible light by the LED. D. It is a measure of the attenuation of the light emitted by the LED. E. It is a measure of the directionality of the LED’s output. F. It is the ratio of the luminous flux of the LED to its power.
- (3 points) What is the name of the process that emits light in an LED? Your answer should be a single word.
- (3 points) Fill in the blanks. The phenomenon described in the previous question takes place when a photon is emitted during (1 word) when a(n) (1 word) joins with a(n) (2 words) and they are annihilated.
- (2 points) Which of the following statements about efficiency droop is false? A. It can be solved by placing more LEDs in the same bulb. B. It is caused by the heat generated by the LED in operation. C. It is correlated with a decrease in the lifetime of an LED. D. It represents the decrease in luminous efficacy as the current through an LED increases. E. It is of larger concern in high current situations. F. It is caused by the Auger Effect. For the next 2 questions, consider an 8-bit ADC that has a voltage measurement range of up to 5 V.
- (2 points) If the ADC is used directly to measure a voltage that can vary between 0 V and 3.3 V, what is its voltage resolution? A. 3.2 mV B. 4.9 mV C. 12.9 mV D. 19.5 mV E. 412.5 mV
A. 50.8 mW B. 41.9 mW C. 40.9 mW D. 33.0 mW E. 10.9 mW F. 8.5 mW
- (2 points) What is the power dissipated by the resistor? A. 1.8 mW B. 10.9 mW C. 26.0 mW D. 8.7 mW E. 41.9 mW F. 40.0 mW
- (4 points) Where does this remaining power go?
- (3 points) Which of the following compounds when placed in a 1 M solution will not conduct electricity? ⃝ NaCH 3 COO ⃝ C 6 H 12 O 6 ⃝ CH 3 COOH ⃝ NaOH ⃝ C 2 H 5 OH ⃝ CH 3 OH
- (3 points) Which of the following are weak electrolytes? ⃝ HBr ⃝ HI ⃝ HF ⃝ NH 3 ⃝ H 2 CO 3 ⃝ HCOOH
- (2 points) 0.01 M of which of the following compounds will result in the solution with the highest conductivity? A. NaCl B. NaBr C. NaOH D. NaCH 3 COO E. NaNO 3 F. NaF
- (4 points) Will 1 M NaCl or 1 M MgCl 2 have a higher conductivity and why? Use the following circuit diagram for the next 5 questions.
- (4 points) Suppose that a voltmeter is connected across the 4.1 kΩ resistor. Find the unknown resistance R in terms of the voltage reading Vout.
- (6 points) Assume the voltmeter has an uncertainty of δVout = ±10 mV and the unknown resistor has a resistance of R = 3000 Ω. What voltage would the voltmeter read? What would the uncertainty in the calculated unknown resistance be?
- (4 points) Suppose the voltmeter is instead connected across the unknown resistor. Find the unknown resistance R in terms of the voltage reading Vout.
- (6 points) Assume again that the voltmeter has an uncertainty of δVout = ±10 mV and the unknown resistor has a resistance of R = 3000 Ω. What voltage would the voltmeter read in this new scenario? What would the uncertainty in the calculated unknown resistance be?
- (4 points) Now suppose that the exact resistance of the 4.1 kΩ is not known, but it has bands of color Yellow, Brown, Red, and Gold. What is the new uncertainty in the calculated unknown resistance Consider the following scenario for the next 3 questions. A conductivity meter is placed in high-concentration solution of NaCl. A DC voltage is applied across the two electrodes.
- (3 points) Which of the following are true? ⃝ The electrode connected to the positive end is the cathode. ⃝ The electrode connected to the positive end is the anode. ⃝ A current will begin to flow. ⃝ An increase will occur at the anode. ⃝ Oxidation will occur at the anode.
- (4 points) What is the current through the battery?
- (4 points) What is the voltage across the 1 kΩ resistor?
- (4 points) If the 1 kΩ resistor were removed, what would the voltage between its original endpoints be in the resulting circuit?
- (4 points) Describe how a Zener diode can be used in a shunt regulator.
- (4 points) Describe what would occur if an ordinary diode were used instead of a Zener diode in the circuit from the previous question. Use the following data for the next 2 questions. x y 0.2 2. 0.4 3. 0.6 3. 0.8 3. 1.0 3. 1.2 3. 1.4 3. 1.6 3. 1.8 3. 2.0 3.
- (6 points) Perform a linear regression on the data. Your model should be in the form y = a + bx, and be sure to include the r^2 value for the line of best fit.
- (6 points) The data does not appear to be linear in nature. Perform an appropriate transformation to linearize the data and then perform a linear regression on the resulting data set. Include the equation for your model in terms of x and y, and include the r^2 value from the line of best fit on the linearized data.
