Test: Part 4
DO NOT REFER TO THE TEXT WHEN TAKING THIS TEST. A GOOD SCORE IS AT LEAST 37 CORRECT. Answers are in the back of the book. It’s best to have a friend check your score the first time, so you won’t memorize the answers if you want to take the test again.
1. In most microcontrollers, Random Access Memory (RAM) is used to store
(a) programs only.
(b) programs and variables.
(c) data only.
(d) programs and constant values.
(e) nonvolatile data.
2. Figure Test 4-1 illustrates a pressure sensor. What’s the material marked X?
Test 4-1 Illustration for Part 4 Test Question 2.
(a) Quartz crystal
(b) Dielectric foam
(c) Conductive foam
(d) Solid dielectric
(e) Semiconducting foam
3. You’ll notice considerable latency in a geostationary-satellite communications link because of
(a) the polar orbit that the satellite follows.
(b) the satellite’s high altitude.
(c) complicated signal processing in the satellite repeater.
(d) handoffs among multiple satellites.
(e) All of the above
4. A stepper motor shaft rotates
(a) continuously at a speed that you can adjust.
(b) continuously at a speed that you can’t adjust.
(c) only when it receives signals at certain frequencies.
(d) in increments, rather than continuously.
(e) back and forth, reversing at a time interval that you can adjust.
5. Figure Test 4-2 is a block diagram of an audio
Test 4-2 Illustration for Part 4 Test Question 5.
(a) waveform analyzer.
(b) frequency synthesizer.
(c) frequency separator.
(d) graphic equalizer.
(e) timbre adjuster.
6. What’s the technical term for a device that determines the distance to an object by transmitting sound pulses toward it and measuring the echo time?
(a) Acoustar
(b) Sonar
(c) Radar
(d) Sonic ranging
(e) Echo ranging
7. Which of the following statements best describes the role of a CPU?
(a) Fetch and execute program instructions
(b) Regulate the voltage of the microcontroller
(c) Store program code
(d) Store variables
(e) Convert analog readings into digital values
8. Which of the following statements about the Arduino is false?
(a) You can only program an Arduino using a Windows computer.
(b) A USB socket can supply power to an Arduino.
(c) The Arduino needs a computer to program it.
(d) The Arduino Uno can accept plug-in “shields” that fit onto its GPIO pins.
(e) The Arduino Uno has a 16-MHz clock.
9. Which of the following is considered a soft recording medium for audio use?
(a) Compact disk
(b) Flash drive
(c) Analog tape
(d) Digital tape
(e) Vinyl disk
10. Analog inputs usually allow a microcontroller to directly
(a) measure voltages between 0 and 10V.
(b) turn an LED on and off.
(c) measure the current flowing out of a GPIO pin.
(d) measure the resistance of a sensor.
(e) measure voltages between 0 and the supply voltage.
11. The simplest audio waveform, which concentrates all the energy at a single frequency, is a
(a) square wave.
(b) ramp.
(d) triangular wave.
(e) harmonic.
12. In a graded-index optical fiber,
(a) the refractive index is lowest along the central axis, and abruptly increases at a certain distance from that axis.
(b) the refractive index is highest along the central axis, and abruptly decreases at a certain distance from that axis.
(c) the refractive index is lowest along the central axis, and steadily increases as you move outward.
(d) the refractive index is highest along the central axis, and steadily decreases as you move outward.
(e) the refractive index is constant throughout.
13. Figure Test 4-3 is a functional diagram of
Test 4-3 Illustration for Part 4 Test Question 13.
(a) an ordinary infrared-emitting diode (IRED).
(b) an ordinary light-emitting diode (LED).
(c) a vertical-cavity surface-emitting laser (VCSEL).
(d) a photodiode.
(e) a quantum diode.
14. Every Arduino sketch must contain
(a) at least 10 lines of code.
(b) only the function “setup.”
(c) only the function “loop.”
(d) both the functions “setup” and “loop.”
(e) global variables.
15. Visible light from a source that radiates at a single wavelength, and in which all of the wavefronts line up with each other, is called
(a) coherent.
(b) phase-coincidental.
(c) sinusoidal.
(d) polychromatic.
(e) broadband.
16. A half-wavelength vertical antenna, fed at the base and mounted on the surface, radiates efficiently even if the ground conductivity is not very good. That’s because the feed-point impedance is
(a) a pure capacitive reactance.
(b) a pure inductive reactance.
(c) a pure and high resistance.
(d) a pure and low resistance.
(e) zero.
17. An eight-bit analog input will provide a digital numeric value between
(a) 1 and 256.
(b) 0 and 1023.
(c) 1 and 1024.
(d) 0 and 100.
(e) 0 and 255.
18. In an Arduino sketch, the word “const”
(a) must be placed before every variable declaration.
(b) will reduce the amount of flash storage needed for a program if used with any variable whose value never changes.
(c) indicates that a variable is consistent.
(d) should be used only in a function definition.
(e) None of the above
19. In a cavity laser, the lasing medium gets its input energy by means of a process called
(a) coherence.
(b) resonance.
(c) pumping.
(d) driving.
(e) irradiation.
20. Which of the following antenna types has a bidirectional radiation pattern, as opposed to a unidirectional pattern?
(a) Dish
(b) Horn
(c) Helical
(e) Corner reflector
21. A visible-light laser has a vivid, intense hue (“color”) because
(a) the beam is extremely narrow.
(b) the light waves come out in many different phases.
(c) the output energy is spread over a wide range of wavelengths.
(d) the output energy is concentrated at a single wavelength.
(e) its beam contains a tremendous amount of energy.
22. Which of the following statements about PWM is false?
(a) PWM stands for Pulse Width Modulation.
(b) PWM control of an LED results in the LED turning on and off.
(c) PWM outputs are true analog outputs.
(d) With a PWM duty cycle of 50%, the PWM output will be on half the time.
(e) The frequency of PWM pulses is normally configurable.
23. What’s the technical term for the device shown in Fig. Test4-4?
Test 4-4 Illustration for Part 4 Test Question 23.
(a) Booster
(b) Repeater
(c) Remodulator
(d) Reamplifier
(e) Extender
24. The lasing medium in a ruby laser comprises
(a) yttrium and garnet.
(b) aluminum oxide and chromium.
(c) gallium and arsenic.
(d) pure elemental germanium.
(e) indium dioxide.
25. Which of the following statements about “setup” and “loop” is false?
(a) “Setup” will run when the Arduino is powered up.
(b) “Loop” will run repeatedly when the Arduino is powered up.
(c) Pressing the Reset button will result in “setup” being run.
(d) After the “loop” function has run, the Arduino checks for serial programming updates.
(e) “Setup” can contain only one line of code.
26. Which of the following antennas is a parasitic array?
(a) Helical
(b) Broadside
(c) End-fire
(d) Dish
(e) Quad
27. Which of the following devices might cause electromagnetic interference (EMI) to a hi-fi sound system?
(a) Computer
(b) Radio transmitter
(c) Electric power lines
(d) Home appliances
(e) Any of the above
28. What type of cable is totally immune to electromagnetic interference (EMI)?
(a) Bundled wire
(b) Parallel wire
(c) Twisted wire
(d) Helically wound
(e) Fiber-optic
29. When a gas lasing medium has an unusually large number of electrons in high-energy shells, the condition is called
(a) an energy surplus.
(b) excess carrier mobility.
(d) a population inversion.
(e) negative charge surplus.
30. What’s the maximum positive number that can be stored in a variable of type “int” in Arduino C?
(a) 255
(b) 127
(c) 2,147,483,647
(d) 65,535
(e) 32,767
31. In a hi-fi stereo sound system, you might find any, or all, of the following components except one. Which one?
(a) Amplifiers
(b) Loudspeakers
(c) AM/FM tuner
(d) Compact-disk (CD) player
(e) AM/FM transmitter
32. What type of antenna transmits and receives radio waves with circular polarization?
(a) Helical
(b) Broadside
(c) End-fire
(d) Dish
(e) Quad
33. At the feed point, a single-turn, circular-loop antenna a half wavelength in circumference exhibits a
(a) high inductive reactance.
(b) high capacitive reactance.
(c) low radiation resistance.
(d) high radiation resistance.
(e) short circuit.
34. In a hi-fi stereo sound system, which of the following controls allows you to adjust the relative loudness of the left channel versus the right channel?
(a) Tone
(b) Node
(c) Ratio
(d) Harmonic
(e) Balance
35. An external pull-up resistor on a digital input will
(a) stop the switch contacts from “bouncing.”
(b) allow a switch to be connected using a longer lead than would otherwise be possible.
(c) keep it in a low logic state.
(d) allow it to function as an output.
(e) allow it to function as an analog input.
36. The waveform of a note at Middle C from a clarinet differs from the waveform of a note at Middle C from a trumpet. That’s why they don’t sound alike. It reflects a difference in
(a) tone.
(b) pitch.
(c) timbre.
(d) wavelength.
(e) propagation speed.
37. Figure Test 4-5 is a block diagram of a
Test 4-5 Illustration for Part 4 Test Question 37.
(a) cellular repeater.
(b) ham radio transmitter.
(c) modulated-light transmitter.
(d) device that interferes with cell phones.
(e) circuit for testing LEDs and IREDs.
38. Piezoelectric transducers are well suited for use in
(a) ultrasonic intrusion detectors.
(b) hi-fi stereo equipment.
(c) radio antenna systems.
(d) navigation systems.
(e) pressure sensors.
39. The Arduino Uno clock frequency is
(a) 4 MHz.
(b) 8 MHz.
(c) 16 MHz.
(d) 20 MHz.
(e) 80 MHz.
40. If you design a modulated-light communications system for line-of-sight use in clear air at sea level, keep in mind that the most absorption (per kilometer) occurs for the color
(a) red.
(b) orange.
(c) yellow.
(d) green.
(e) blue.
41. At a fixed location, the distance to the radar horizon depends on the
(a) height of the antenna.
(b) contour of the surrounding terrain.
(c) transmitter output power.
(d) weather conditions in the vicinity.
(e) All of the above
42. What purpose can the small loop shown in Fig. Test 4-6 effectively serve?
Test 4-6 IIllustration for Part 4 Test Question 42.
(a) Radio direction finding (RDF) below 20 MHz
(b) Transmitting below 100 kHz
(c) An isotropic receiving antenna at any frequency
(d) The tuned circuit in a microwave oscillator
(e) Transmitting or receiving at any frequency
43. With respect to hi-fi sound systems, what’s the technical term for the ratio of the maximum power output to the minimum power output that the system can produce while maintaining acceptable performance with low distortion?
(a) Dynamic range
(b) Loudness ratio
(c) Power range
(d) Distortion coefficient
(e) Audio output ratio
44. A microcontroller’s digital outputs can be directly connected to
(a) high-power loads such as motors.
(b) switches and sensors.
(c) computer monitors.
(d) low-current loads such as LEDs.
(e) USB peripherals such as printers.
45. A half-wavelength straight wire fed at one end with a quarter-wave section of parallel-wire transmission line is
(a) a zepp antenna.
(b) an open dipole antenna.
(c) a longwire antenna.
(d) an isotropic antenna.
(e) a quarter-dipole antenna.
46. Which of the following devices comprises a coil-and-magnet assembly that converts varying electric currents into sound waves?
(a) Acoustic converter
(b) Acoustic repeater
(c) RF transducer
(d) Loudspeaker
(e) DC transducer
47. The Arduino’s six pins labeled A0 to A5
(a) can only be used as analog inputs.
(b) can be used as analog inputs or analog outputs.
(c) can only be used as analog or digital inputs.
(d) can be used as analog input, digital input or digital output.
(e) should not be used.
48. What’s the diameter of multimode optical fiber?
(a) At least 10 times the longest wavelength to be carried
(b) Less than 10 times the shortest wavelength to be carried
(c) At least 10 nanometers (nm)
(d) Less than 10 nm
(e) It doesn’t matter
49. Which of the following systems operates at the shortest wavelength?
(a) Radar
(b) Global Positioning System (GPS)
(c) Photoelectric proximity sensor
(d) Loran
(e) FM broadcast station
50. A quantum number expresses
(a) the amount of energy in a light beam.
(b) the wavelength of a photon.
(c) the total number of electrons in an atom.
(d) an electron’s energy level in an atom.
(e) the extent to which energy waves are coherent.