Technology (Grades 5–12)
Subtest 2 Sample Items
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Question 1
1. Fiber-optic cables transmit data via light pulses through the process of:
- stimulated emission of photons.
- photoelectric emission.
- energy band transitions.
- total internal reflection.
Answer to question 1
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0011) Fiber-optic cable is constructed with a transparent core material having a higher index of refraction than its surrounding clad material. Light striking the interface between the core and cladding at an angle greater than the critical angle is reflected back into the core. This effect of total internal reflection results in a low-loss transmission of light through the cable.
Correct Response: D. (Objective 0011) Fiber-optic cable is constructed with a transparent core material having a higher index of refraction than its surrounding clad material. Light striking the interface between the core and cladding at an angle greater than the critical angle is reflected back into the core. This effect of total internal reflection results in a low-loss transmission of light through the cable.
Question 2
2. Shielded cables are used for connecting peripherals to I/O ports on a computer in order to:
- minimize shock hazard.
- prevent interference from electrical noise.
- prevent interference from electrical noise.
- increase data transmission speed.
Answer to question 2
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0011) Cables connecting computers and peripherals can act as an antenna that will pick up and carry electromagnetic noise into these devices. A shielded cable utilizes a conducting surface, or shield, to surround one or more data-carrying inner conductors. When properly connected, the shield effectively directs any induced noise currents to the ground.
Correct Response: B. (Objective 0011) Cables connecting computers and peripherals can act as an antenna that will pick up and carry electromagnetic noise into these devices. A shielded cable utilizes a conducting surface, or shield, to surround one or more data-carrying inner conductors. When properly connected, the shield effectively directs any induced noise currents to the ground.
Question 3
3. The individual wires inside an Ethernet cable are arranged in twisted pairs by color. When installing terminals on the ends of Ethernet cables, it is important that the twisting extends as close as possible to the terminals. Which of the following is the most important reason for this requirement?
- avoiding crosstalk
- maximizing tensile strength
- matching impedance
- increasing the signal-to-noise ratio
Answer to question 3
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0011) The conductors inside an Ethernet cable are arranged in twisted pairs. This makes them less susceptible to noise from outside electromagnetic sources and it also minimizes the effect of the signal in one pair inducing a signal in another pair. This type of inductive pair-to-pair noise is known as crosstalk. The main way that twisting reduces crosstalk is by making sure that no conductor within the pair is closer than the other to the interference source on average over the course of the run. This assures that both strands are equally affected and allows the noise generated to be subtracted out. Every time an Ethernet cable is terminated, there is a short length through which the conductors are not twisted. To avoid crosstalk, these untwisted lengths must be kept as short as possible.
Correct Response: A. (Objective 0011) The conductors inside an Ethernet cable are arranged in twisted pairs. This makes them less susceptible to noise from outside electromagnetic sources and it also minimizes the effect of the signal in one pair inducing a signal in another pair. This type of inductive pair-to-pair noise is known as crosstalk. The main way that twisting reduces crosstalk is by making sure that no conductor within the pair is closer than the other to the interference source on average over the course of the run. This assures that both strands are equally affected and allows the noise generated to be subtracted out. Every time an Ethernet cable is terminated, there is a short length through which the conductors are not twisted. To avoid crosstalk, these untwisted lengths must be kept as short as possible.
Question 4
4. The scale on a drawing is 1 inch equals 25 feet. What is the approximate length of a fence that has a length of 20 inches in the drawing?
- 100 feet
- 200 feet
- 250 feet
- 500 feet
Answer to question 4
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0012) Scale drawings use smaller measurements that can fit on a paper drawing to represent actual measurements of the finished product. In this case, one inch on the paper drawing represents 25 feet on the finished product. Since the scale is one inch = 25 feet and the drawing of the fence is 20 inches long, the length of the fence is 25 x 20 or 500 feet.
Correct Response: D. (Objective 0012) Scale drawings use smaller measurements that can fit on a paper drawing to represent actual measurements of the finished product. In this case, one inch on the paper drawing represents 25 feet on the finished product. Since the scale is one inch = 25 feet and the drawing of the fence is 20 inches long, the length of the fence is 25 times 20 or 500 feet.
Question 5
5. Which of the following best identifies the circuit shown below?
From left to right, the voltage source connects to one side of a paired set of inductors with a magnetic core, the left has the voltage source at the two terminals and the right is connected to either side of the second component, a system of four diodes connected in a circuit. The diodes are flowing clockwise on one side and counter clockwise on the other, away from the left and towards the right. The diodes are then connected to the third component. The left side of the diode combination is connected to the ground, and the right side is connected to two capacitors in series. The capacitors are then connected to on either side in two terminals, one labeled plus and one minus.
- oscillator
- audio amplifier
- power supply
- modulator
Answer to question 5
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0012) An electronic power supply consists of three main components with different functions. A transformer steps up or down the AC input voltage. One or more diodes rectify (pass current in one direction) the AC, producing pulsating DC voltage. Capacitors, due to relatively slow discharge time, smooth the pulses into steady DC voltage.
Correct Response: C. (Objective 0012) An electronic power supply consists of three main components with different functions. A transformer steps up or down the AC input voltage. One or more diodes rectify (pass current in one direction) the A C, producing pulsating D C voltage. Capacitors, due to relatively slow discharge time, smooth the pulses into steady D C voltage.
Question 6
6. Which of the following is a type of pictorial representation of an object in which all three dimensions are drawn at the same scale?
- isometric
- oblique
- orthographic
- perspective
Answer to question 6
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0012) Isometric, from iso-, and metric, literally means "same measure." An isometric projection depicts an object with dimensions along the x, y, and z axes drawn to the same scale. This type of drawing allows the relative sizes of drawing components to be easily determined.
Correct Response: A. (Objective 0012) start italics Isometric end italics, from iso-, and metric, literally means "same measure." An isometric projection depicts an object with dimensions along the x, y, and z axes drawn to the same scale. This type of drawing allows the relative sizes of drawing components to be easily determined.
Question 7
7. Use the engineering drawing below to answer the question that follows.
The drawing consists of a circle within a rectangular box. The circle has a horizontal center line and a vertical center line. A leader is drawn from the circle to outside the box. At the end of the leader is a circle, the size of the letter "O", with a slanted line (forward slash) drawn from the upper right to the lower left of the circle. Next to the symbol is the number 9.
Which aspect of the circle above is specified to have a measure of 9 units?
- radius
- diameter
- area
- circumference
Answer to question 7
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0012) When dimensioning a circle in an engineering drawing, the convention is to specify the diameter using the circle and slash symbol.
Correct Response: C. (Objective 0012) When dimensioning a circle in an engineering drawing, the convention is to specify the diameter using the circle and slash symbol.
Question 8
8. Which of the following letters is symmetric about a line?
- E
- G
- P
- J
Answer to question 8
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0013) Symmetry about a line means that a line can be drawn through an object, drawing, design, or other representation that divides it into two identical halves. In this case, a horizontal line can be drawn through the middle of the center bar in the letter "E" and everything above the line will be identical to everything below the line.
Correct Response: A. (Objective 0013) Symmetry about a line means that a line can be drawn through an object, drawing, design, or other representation that divides it into two identical halves. In this case, a horizontal line can be drawn through the middle of the center bar in the letter "E" and everything above the line will be identical to everything below the line.
Question 9
9. Which of the following printing technologies uses electrostatic attraction between ink and paper to create an image?
- lithography
- screen printing
- photocopy
- gravure printing
Answer to question 9
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0013) Photocopiers initially transfer a representative image of the copied material by electrostatically charging areas of the paper that are to receive ink particles. Attraction between the oppositely charged ink and print regions produces a visible image, which is then made permanent by heating, which fuses the ink to the paper.
Correct Response: C. (Objective 0013) Photocopiers initially transfer a representative image of the copied material by electrostatically charging areas of the paper that are to receive ink particles. Attraction between the oppositely charged ink and print regions produces a visible image, which is then made permanent by heating, which fuses the ink to the paper.
Question 10
10. The audio portion of a multimedia presentation does not adequately reproduce low-frequency source information. Which of the following information processing functions of controlling equipment would be used to correct this?
- noise filtering
- attenuation
- frequency modulation
- equalization
Answer to question 10
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0013) An equalizer is designed to provide emphasis, or de-emphasis, of a particular band of audio frequencies in sound equipment. In this situation, an adjustment of the low, or bass, frequency gain would be made to increase output in this region of the audio spectrum.
Correct Response: D. (Objective 0013) An equalizer is designed to provide emphasis, or de-emphasis, of a particular band of audio frequencies in sound equipment. In this situation, an adjustment of the low, or bass, frequency gain would be made to increase output in this region of the audio spectrum.
Question 11
11. In which of the following situations would the use of a lossy compression algorithm be most appropriate?
- converting a document into a format that can be viewed using any operating system
- preparing a large photograph to embed in an HTML file
- archiving a report that contains graphics, charts, and mathematical equations
- preparing the source code of a computer program for users to download from a Web server
Answer to question 11
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0013) Compression is the process of encoding digital data in a different format to reduce file size. There are two types of compression methods or algorithms: lossless and lossy. Lossless compression allows the data in the file to be completely recovered. Lossy compression removes certain information permanently. When the file is reconstructed, it is only an approximation of the original file. Lossy compression is usually used for images, video, and sound, where the loss is not detected by most users. Photographs and other images on the Web use lossy compression to reduce the amount of time needed to display the image in a browser, which reads HTML files. The JPEG image format is an example of a lossy compression algorithm.
Correct Response: B. (Objective 0013) Compression is the process of encoding digital data in a different format to reduce file size. There are two types of compression methods or algorithms: lossless and lossy. Lossless compression allows the data in the file to be completely recovered. Lossy compression removes certain information permanently. When the file is reconstructed, it is only an approximation of the original file. Lossy compression is usually used for images, video, and sound, where the loss is not detected by most users. Photographs and other images on the Web use lossy compression to reduce the amount of time needed to display the image in a browser, which reads HTML files. The JPEG image format is an example of a lossy compression algorithm.
Question 12
12. The uplink and downlink equipment used in satellite communications send and receive data via which of the following?
- microwave radio frequencies
- infrared light pulses
- shortwave radio frequencies
- laser light pulses
Answer to question 12
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0014) Microwave radio frequencies can pass through the ionosphere with relatively little loss of energy, and their very short wavelength allows for small antenna size. Although somewhat affected by local weather conditions (e.g., heavy rain and snow) they provide a reliable channel to utilize for this purpose.
Correct Response: A. (Objective 0014) Microwave radio frequencies can pass through the ionosphere with relatively little loss of energy, and their very short wavelength allows for small antenna size. Although somewhat affected by local weather conditions (e.g., heavy rain and snow) they provide a reliable channel to utilize for this purpose.
Question 13
13. Use the diagram below to answer the question that follows.
First box is encode transmit. This box points to another box which reads channel. This box point in two directions: one to receive decode, another south to a box labeled X. The box labeled X points north to the arrow extending from encode transmit to channel.
Which of the following communications system functions is performed by the block labeled "X"?
- modulation
- rectification
- feedback
- recording
Answer to question 13
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0014) A feedback loop is used in a communications system to ensure that the information arriving at the receiver is identical to that which was sent by the transmitter. In this diagram, the feedback function block provides a return path for a signal to travel from receiver/decoder to transmitter/encoder.
Correct Response: C. (Objective 0014) A feedback loop is used in a communications system to ensure that the information arriving at the receiver is identical to that which was sent by the transmitter. In this diagram, the feedback function block provides a return path for a signal to travel from receiver/decoder to transmitter/encoder.
Question 14
14. A computer workstation is located in an environment where the frequent on-off cycling of electrical equipment causes line voltage fluctuations with occasional high voltage spikes. Which of the following steps would be appropriate to provide protection to the computer?
- installing larger fuses in the computer
- using a GFCI in the branch circuit wiring
- installing a large circuit breaker
- using a surge suppressor in the AC line input
Answer to question 14
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0014) A line voltage surge suppressor is placed between a building's electrical distribution wiring and the device(s) being protected. Surge suppressors are designed to absorb brief over-voltage conditions and to safely dissipate this energy as heat.
Correct Response: D. (Objective 0014) A line voltage surge suppressor is placed between a building's electrical distribution wiring and the device(s) being protected. Surge suppressors are designed to absorb brief over-voltage conditions and to safely dissipate this energy as heat.
Question 15
15. Which of the following best describes a primary feature of layered telecommunications protocols?
- Information is evaluated in terms of its priority and routed to its destination accordingly
- Large, complicated tasks are broken down into independent sets of rules for handling very specific tasks.
- Analog data is sampled at various rates without affecting the bandwidth of the transmission signal.
- Multiple digital signals are combined into a single signal for transmission and decomposed into its original signals upon reception.
Answer to question 15
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0014) A line voltage surge suppressor is placed between a building's electrical distribution wiring and the device(sA communication protocol is a set of rules that allow a system to transmit information. Modern communication protocols are layered and consist of a stack of protocols that work together to exchange information. Each layer of the protocol performs a specific function. For example, one layer may encode information, while another layer addresses the message, and a third layer checks if the messages should be resent.
Correct Response: B. (Objective 0014) A communication protocol is a set of rules that allow a system to transmit information. Modern communication protocols are layered and consist of a stack of protocols that work together to exchange information. Each layer of the protocol performs a specific function. For example, one layer may encode information, while another layer addresses the message, and a third layer checks if the messages should be resent.
Question 16
16. Stainless steel, which resists corrosion and rusting far better than ordinary steel, typically consists of around 11 percent by mass of which of the following elements?
- chromium
- nickel
- tungsten
- carbon
Answer to question 16
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0015) Unprotected carbon steel forms iron oxide (rust) on its surface when exposed to air. This rust is prone to flaking, exposing more unprotected metal and causing more rust to form. Chromium oxide does not rust and when chromium is added to steel it forms a thin barrier of chromium oxide on the surface of the metal. Moreover, if this barrier is scratched, more chromium oxide will form and the metal remains resistant to oxidation.
Correct Response: A. (Objective 0015) Unprotected carbon steel forms iron oxide (rust) on its surface when exposed to air. This rust is prone to flaking, exposing more unprotected metal and causing more rust to form. Chromium oxide does not rust and when chromium is added to steel it forms a thin barrier of chromium oxide on the surface of the metal. Moreover, if this barrier is scratched, more chromium oxide will form and the metal remains resistant to oxidation.
Question 17
17. Use the figure of a candlestick shown below to answer the question that follows.
A woodworking shop makes decorative candlesticks such as the one shown. Which of the following computer numerical control (CNC) tools would be used to shape the candlestick from a wooden blank into its final form?
- router
- lathe
- high-speed sander
- milling machine
Answer to question 17
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0015) A lathe consists of a spindle that rapidly rotates a piece of wood or metal while cutting tools are pressed against the piece to remove material. Sandpaper can be held against the material as it turns to produce a finer finish. In the case of the wooden candlestick, a block of wood attached to the spindle was spun rapidly, while cutting blades positioned by CNC commands removed material to form the curves of the candlestick.
Correct Response: B. (Objective 0015) A lathe consists of a spindle that rapidly rotates a piece of wood or metal while cutting tools are pressed against the piece to remove material. Sandpaper can be held against the material as it turns to produce a finer finish. In the case of the wooden candlestick, a block of wood attached to the spindle was spun rapidly, while cutting blades positioned by C N C commands removed material to form the curves of the candlestick.
Question 18
18. A silicon elastomer with a high silicon content is preferred for products when:
- softness and malleability are most important.
- the product must return to its original shape after deformation.
- strength and resistance to wear are most important.
- the product will be exposed to high temperatures.
Answer to question 18
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0015) An elastomer is a polymer with a low Young's modulus and a high yield strain. Rubber is an example of a widely used elastomer. Elastomers are usually made up of carbon, hydrogen, oxygen, and silicon. Since silicon has a high melting point, elastomers that contain a larger amount of silicon will usually be more heat tolerant than those that don't and silicon elastomers are often used in applications where heat resistance is important.
Correct Response: D. (Objective 0015) An elastomer is a polymer with a low Young's modulus and a high yield strain. Rubber is an example of a widely used elastomer. Elastomers are usually made up of carbon, hydrogen, oxygen, and silicon. Since silicon has a high melting point, elastomers that contain a larger amount of silicon will usually be more heat tolerant than those that don't and silicon elastomers are often used in applications where heat resistance is important.
Question 9
19. A manufacturer of decorative tiles uses a diamond-encrusted circular saw blade to cut the tiles from glazed ceramic stock. To most effectively cut through the stock, which of the following is most likely to be applied during the cutting process?
- lithium grease
- oil
- graphite powder
- water
Answer to question 19
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0015) When cutting through hard, brittle materials such as ceramic, porcelain, and stone, it is common to use a diamond-encrusted circular saw. The saw blade must be constantly bathed in water to keep it from overheating. Overheating the blade can result in an increased likelihood of chipping or cracking the stock. Overheating can also damage the blade. In addition to cooling the blade, the water also performs other functions such as lubrication and dust reduction.
Correct Response: D. (Objective 0015) When cutting through hard, brittle materials such as ceramic, porcelain, and stone, it is common to use a diamond-encrusted circular saw. The saw blade must be constantly bathed in water to keep it from overheating. Overheating the blade can result in an increased likelihood of chipping or cracking the stock. Overheating can also damage the blade. In addition to cooling the blade, the water also performs other functions such as lubrication and dust reduction.
Question 20
20. Which of the following is one potential disadvantage of using just-in-time inventory control techniques in manufacturing?
- Delay in obtaining one of the components used in the manufacturing process can stall production and disrupt scheduling.
- The manufacturer has very little control over the quality of the components that the manufacturer's suppliers ship.
- The manufacturer must pay current prices for components when they are needed rather than stockpiling components at a lower price.
- The necessity of dealing with many small suppliers rather than one large supplier adds to purchasing and paperwork costs.
Answer to question 20
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0016) Just-in-time (JIT) inventory control techniques are often used to lower costs by not maintaining an inventory of materials, parts, or components at the assembly or manufacturing plant. This reduces storage costs in particular. JIT requires parts to arrive at the assembly or manufacturing facility as they are needed rather than being stored on site. However, if a critical shipment of a material or part is held up, the entire production process may shut down whereas in a traditional inventory system enough supplies of all critical materials would be kept on hand and replenished when they run low and before lack of a material or part could jeopardize the production process.
Correct Response: A. (Objective 0016) Just-in-time (J I T) inventory control techniques are often used to lower costs by not maintaining an inventory of materials, parts, or components at the assembly or manufacturing plant. This reduces storage costs in particular. J I T requires parts to arrive at the assembly or manufacturing facility as they are needed rather than being stored on site. However, if a critical shipment of a material or part is held up, the entire production process may shut down whereas in a traditional inventory system enough supplies of all critical materials would be kept on hand and replenished when they run low and before lack of a material or part could jeopardize the production process.
Question 21
21. Extraction of which of the following metals consumes the most electricity?
- copper
- aluminum
- tin
- iron
Answer to question 21
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0016) Aluminum is removed from bauxite ore through electrolysis rather than smelting. Bauxite is first heated, then cooled, several minerals are added, and then the mixture is heated to form aluminum oxide. Pure aluminum is obtained by passing an electric current through the molten material causing the aluminum to precipitate out. Aluminum refining consumes nearly 5 percent of the electricity used in the United States.
Correct Response: B. (Objective 0016) Aluminum is removed from bauxite ore through electrolysis rather than smelting. Bauxite is first heated, then cooled, several minerals are added, and then the mixture is heated to form aluminum oxide. Pure aluminum is obtained by passing an electric current through the molten material causing the aluminum to precipitate out. Aluminum refining consumes nearly 5 percent of the electricity used in the United States.
Question 22
22. A coffee manufacturer roasts beans in batches of 500 pounds. After each batch is roasted, some of the beans are taken and inspected for smell, appearance, taste, and chemical properties. Despite this quality control procedure, the manufacturer has received customer complaints of both under-roasted and over-roasted beans. Which of the following aspects of the quality control process is most likely to be the problem?
- sampling
- measurement
- timing
- parameter setting
Answer to question 22
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0016) The problem appears to be that over- and under-roasted beans are getting through the process without being sampled. It is important that samples are taken in such a way that they are representative of the entire batch of beans. Perhaps samples should be taken from a variety of locations within the batch, or the batch may need to be mixed up before sampling to assure that all parts of the batch are included.
Correct Response: A. (Objective 0016) The problem appears to be that over- and under-roasted beans are getting through the process without being sampled. It is important that samples are taken in such a way that they are representative of the entire batch of beans. Perhaps samples should be taken from a variety of locations within the batch, or the batch may need to be mixed up before sampling to assure that all parts of the batch are included.
Question 23
23. A worker at a drill press is using a 2' × 2' template to drill holes in sheet-metal workpieces that are 6' × 4'. Each of the 6' × 4' workpieces is later cut into six 2' × 2' workpieces by a band saw. Which of the following changes would be most appropriate to make to this process?
A worker at a drill press is using a 2 foot by 2 foot template to drill holes in sheet-metal workpieces that are 6 feet by 4 feet. Each of the 6 foot by 4 foot workpieces is later cut into six 2 foot by 2 foot workpieces by a band saw. Which of the following changes would be most appropriate to make to this process?
- Create a larger template.
- Change the sequence of steps.
- Replace the band saw with a radial arm saw.
- Replace the drill press with a milling machine.
Answer to question 23
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0017) The main problem in using a drill press, which generally will have a relatively small support surface, to drill holes in a 6' × 4' workpiece is that such a large workpiece will be difficult to support and maneuver. Since the larger piece will be cut into smaller 2' × 2' pieces that match the size of the template, it would be much easier to cut the 6' × 4' piece into 2' × 2' pieces before drilling. The smaller pieces will match the size of the template, be much easier to move about, and be better supported by the table of the drill press.
Correct Response: B. (Objective 0017) The main problem in using a drill press, which generally will have a relatively small support surface, to drill holes in a 6 foot by 4 foot workpiece is that such a large workpiece will be difficult to support and maneuver. Since the larger piece will be cut into smaller 2 feet by 2 feet pieces that match the size of the template, it would be much easier to cut the 6 foot by 4 foot piece into 2 foot by 2 foot pieces before drilling. The smaller pieces will match the size of the template, be much easier to move about, and be better supported by the table of the drill press.
Question 24
24. A long, hollow piece of plastic, such as a pipe, would most likely be produced using which of the following processes?
- extrusion
- casting
- injection molding
- thermoforming
Answer to question 24
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0017) Extrusion is a plastics manufacturing process in which polymer resin is heated to a molten state in a chamber, and then pushed by a screw through a die. As the plastic emerges, it assumes the shape of the die and is then cooled in the air, or by passing through a water bath. Since extrusion can be a continuous process, with more resin being constantly added, heated, pushed by the screw, and passed through the die, it is especially suitable for forming long, continuous shapes such as pipes.
Correct Response: A. (Objective 0017) Extrusion is a plastics manufacturing process in which polymer resin is heated to a molten state in a chamber, and then pushed by a screw through a die. As the plastic emerges, it assumes the shape of the die and is then cooled in the air, or by passing through a water bath. Since extrusion can be a continuous process, with more resin being constantly added, heated, pushed by the screw, and passed through the die, it is especially suitable for forming long, continuous shapes such as pipes.
Question 25
25. Which of the following best describes one advantage of die casting metal parts rather than using a sand casting technique?
- Larger items can be casted using die casting.
- Surface finish and detail on die-casted parts are much better.
- Die casting can cast both ferrous and nonferrous material.
- Tooling costs for die-casted parts are lower.
Answer to question 25
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0017) In die casting, molten metal is poured or pushed into the cavity inside a tooled die and then cooled, resulting in a part that takes the shape of the cavity of the die. In sand casting, a pattern having the shape of the final part is pressed into sand to make an imprint and the molten metal is poured into this imprint. Sand casting can make larger parts than die casting and costs are lower since complex dies are not required. However, die-cast parts have a finer surface finish because the interior of the die can be made smooth and polished.
Correct Response: B. (Objective 0017) In die casting, molten metal is poured or pushed into the cavity inside a tooled die and then cooled, resulting in a part that takes the shape of the cavity of the die. In sand casting, a pattern having the shape of the final part is pressed into sand to make an imprint and the molten metal is poured into this imprint. Sand casting can make larger parts than die casting and costs are lower since complex dies are not required. However, die-cast parts have a finer surface finish because the interior of the die can be made smooth and polished.
Question 26
26. A team of students is designing a robotic manipulator arm for accurately positioning a workpiece for CNC drilling. The students would most likely select a servo motor instead of a stepper motor to meet which of the following criteria?
- The motor will operate at a high speed and will need to respond to feedback based on sensor input data about its position.
- The motor will operate as a low-power open-loop system that will need to rotate incrementally through specific angles.
- The motor will operate as the power source for a hydraulic pump that uses pistons to control the movement of the arm.
- The motor will operate at a continuous high-speed rotation with little or no need to control the motor's speed or shaft position.
Answer to question 26
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0017) Manipulator arms are robots that model the movement of the human arm and can perform a range of manufacturing tasks. A variety of different motors are used as actuators to move and control the manipulator. Applications that require precise positioning and high speeds typically involve the use of servo motors. Servo motors operate by pulsed width modulation (PWM) and involve a built-in sensor (encoder) that captures the position of the motor. Servo motors contain a control unit and use a closed-loop feedback system to read and adjust the position of the shaft as needed.
Correct Response: A. (Objective 0017) Manipulator arms are robots that model the movement of the human arm and can perform a range of manufacturing tasks. A variety of different motors are used as actuators to move and control the manipulator. Applications that require precise positioning and high speeds typically involve the use of servo motors. Servo motors operate by pulsed width modulation (PWM) and involve a built-in sensor (encoder) that captures the position of the motor. Servo motors contain a control unit and use a closed-loop feedback system to read and adjust the position of the shaft as needed.
Question 27
27. Which of the following best describes the relationship between a gene and a chromosome?
- A gene is the molecule from which chromosomes are made.
- A gene is a functional unit of a chromosome.
- A chromosome is the molecule from which genes are made.
- A chromosome is a functional unit of a gene.
Answer to question 27
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0018) A chromosome is a string of DNA. DNA consists of discrete proteins called nucleotides that are "read" in units of three. A gene is typically defined as a space on a chromosome consisting of a string of nucleotide "words." The gene may code for the synthesis of a particular amino acid. Amino acids are the building blocks of proteins.
Correct Response: B. (Objective 0018) A chromosome is a string of DNA. DNA consists of discrete proteins called nucleotides that are "read" in units of three. A gene is typically defined as a space on a chromosome consisting of a string of nucleotide "words." The gene may code for the synthesis of a particular amino acid. Amino acids are the building blocks of proteins.
Question 28
28. In genetic engineering, in which genes from a donor organism are transferred to the cell of a different host organism, ligase enzymes are used to:
- cut the gene which is to be transferred from the DNA sequence of the donor cell.
- disrupt the membrane of the host's cell to allow the plasmid carrier into the cell.
- bind the gene from the donor cell to the plasmid carrier that will carry it into the host's cell.
- stimulate cloning of the recombinant cell after the donor's gene has been transferred to the host.
Answer to question 28
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0018) In gene transfer, once a desirable gene to be transferred has been identified in a donor cell, the gene is cut from the DNA by the use of restriction enzymes. The gene must then be transferred into a bacterial plasmid or virus that can be used to carry the donor gene into the host cell. Ligases are enzymes that are able to join together the ends of two large molecules and are used to insert the donated gene into the DNA of the plasmid before it is incorporated into the host cell.
Correct Response: C. (Objective 0018) In gene transfer, once a desirable gene to be transferred has been identified in a donor cell, the gene is cut from the D N A by the use of restriction enzymes. The gene must then be transferred into a bacterial plasmid or virus that can be used to carry the donor gene into the host cell. Ligases are enzymes that are able to join together the ends of two large molecules and are used to insert the donated gene into the D N A of the plasmid before it is incorporated into the host cell.
Question 29
29. Genes from animals, including humans, have been transplanted into bacteria, typically start italics E. coli end italics . The genetically modified start italics E. coli end italics are then cloned and grown in large vats to produce which of the following substances?
- antibiotics such as ampicillin, tetracycline, and neomycin
- cells such as skin cells, muscle cells, or nerve cells
- nutrients such as proteins, fats, and carbohydrates
- hormones such as insulin and bovine somatotropin
Answer to question 29
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0018) The human gene that produces insulin and the bovine gene that produces bovine somatotropin are two of the most widely cited examples of the benefits of creating transgenic organisms. In both cases, the donor gene from human or bovine cells is transferred into E. coli bacteria. Another gene which confers resistance to a specific antibiotic is also transferred. Exposure of the colony to the antibiotic kills off those E. coli that lack the human or bovine gene, yielding a pure culture of transgenic bacteria. These are grown in large vats and produce the desired hormone as a by-product of their metabolism.
Correct Response: D. (Objective 0018) The human gene that produces insulin and the bovine gene that produces bovine somatotropin are two of the most widely cited examples of the benefits of creating transgenic organisms. In both cases, the donor gene from human or bovine cells is transferred into start italics E. coli end italics bacteria. Another gene which confers resistance to a specific antibiotic is also transferred. Exposure of the colony to the antibiotic kills off those start italics E. coli end italics that lack the human or bovine gene, yielding a pure culture of transgenic bacteria. These are grown in large vats and produce the desired hormone as a by-product of their metabolism.
Question 30
30. Selective breeding has been used since the beginning of agriculture to create the plants and animals that are used in today's food industry. This process continues today as farmers strive to increase disease resistance, nutritional value, and productivity in crops and livestock. Modern biotechnology techniques involving genetic engineering have added another tool to help achieve these goals. Which of the following is the best example of an advantage of genetic engineering over selective breeding?
- increased control
- higher predictability
- faster results
- decreased cost
Answer to question 30
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0018) While selective breeding only produces results after many generations of plants or animals, genetic engineering can produce results within only one or two generations.
Correct Response: C. (Objective 0018) While selective breeding only produces results after many generations of plants or animals, genetic engineering can produce results within only one or two generations.
Question 31
31. One disadvantage of using ceramic materials in a project is that ceramics are typically:
- brittle.
- sensitive to corrosives.
- soft.
- sensitive to heat.
Answer to question 31
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0019) Ceramics are materials, such as pottery, tiles, thermal or electric insulators, and bricks that are made of clay that has been hardened by exposure to high heat. Ceramics are hard, wear-resistant, heat-resistant, and chemically stable. They are also brittle because of the type of bonding between the atoms that make up the structure of the material.
Correct Response: A. (Objective 0019) Ceramics are materials, such as pottery, tiles, thermal or electric insulators, and bricks that are made of clay that has been hardened by exposure to high heat. Ceramics are hard, wear-resistant, heat-resistant, and chemically stable. They are also brittle because of the type of bonding between the atoms that make up the structure of the material.
Question 32
32. A worker would most likely use a dado blade in a circular or radial arm saw to accomplish which of the following?
- cutting a groove of selected width and depth through wood for a joint
- making a smooth cut through plywood with minimal splintering
- making a beveled cut for a joint though a thick piece of wood
- cutting extremely hard wood or tile without shattering or cracking the piece
Answer to question 32
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0019) The most common type of dado blade consists of two circular saw blades with a chipper blade in between. The object of using the blade is to cut a kerf in wood without penetrating all the way through the piece. The width of the kerf can be adjusted by adding or subtracting spacers or choppers to expand or reduce the kerf width. The depth of the kerf can be varied by raising or lowering the blade. The kerf forms a groove thorough the wood that serves as the female part of a dado joint. Gluing in a corresponding male part that fits the width and depth of the groove forms a strong, tight joint known as a dado joint and is often used in making drawers in desks or bureaus.
Correct Response: A. (Objective 0019) The most common type of dado blade consists of two circular saw blades with a chipper blade in between. The object of using the blade is to cut a kerf in wood without penetrating all the way through the piece. The width of the kerf can be adjusted by adding or subtracting spacers or choppers to expand or reduce the kerf width. The depth of the kerf can be varied by raising or lowering the blade. The kerf forms a groove thorough the wood that serves as the female part of a dado joint. Gluing in a corresponding male part that fits the width and depth of the groove forms a strong, tight joint known as a dado joint and is often used in making drawers in desks or bureaus.
Question 33
33. Plans for construction of a large atrium in a house call for the use of long, unsupported beams. Which of the following materials would be the best choice for this purpose where strength in compression and tension, low elastic modulus, deflection, low weight, and resistance to warping, twisting, or shrinking are all important considerations?
- kiln-dried softwood beams such as spruce, pine, or fir
- green hardwood beams such as oak or ash
- reinforced concrete beams
- beams made from laminated veneer lumber
Answer to question 33
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: D. (Objective 0019) Laminated veneer lumber is analogous to plywood in that it consists of thin pieces of wood that are strongly bonded together with adhesives. Because the individual pieces of wood are thin, a beam made of laminated veneer lumber is much less subject to warping, twisting, or shrinking. Laminated veneer lumber also lacks defects such as knots or splits that might be present in solid beams and, as a consequence, is stronger in both compression and tension with less weight and size of the beam. Laminated veneer lumber thus allows longer beam lengths with lower weight than other types of materials.
Correct Response: D. (Objective 0019) Laminated veneer lumber is analogous to plywood in that it consists of thin pieces of wood that are strongly bonded together with adhesives. Because the individual pieces of wood are thin, a beam made of laminated veneer lumber is much less subject to warping, twisting, or shrinking. Laminated veneer lumber also lacks defects such as knots or splits that might be present in solid beams and, as a consequence, is stronger in both compression and tension with less weight and size of the beam. Laminated veneer lumber thus allows longer beam lengths with lower weight than other types of materials.
Question 34
34. An engineer would be most likely to use a material's linear coefficient of thermal expansion when:
- determining space to be left between each rail laid end-to-end on a railroad track.
- calculating the thickness of a freestanding brick wall around a garden.
- estimating the amount of concrete needed to line a drainage ditch in a field.
- deciding on the amount of sand and cement in mortar used in the brick facade of a building.
Answer to question 34
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0019) The coefficient of thermal expansion determines the amount that a particular material shrinks or expands when exposed to temperature changes. Railroad lines laid end-to-end must have a space between each rail to allow for expansion of the rails during high temperatures. Lines that have been laid with a gap that is too narrow have been known to buckle as the gap closes and the rails push against each other. Several serious train wrecks have resulted from this miscalculation.
Correct Response: A. (Objective 0019) The coefficient of thermal expansion determines the amount that a particular material shrinks or expands when exposed to temperature changes. Railroad lines laid end-to-end must have a space between each rail to allow for expansion of the rails during high temperatures. Lines that have been laid with a gap that is too narrow have been known to buckle as the gap closes and the rails push against each other. Several serious train wrecks have resulted from this miscalculation.
Question 35
35. A house has been framed, roofed, and the doors and windows put on. The start italics next end italics step in the construction of the house interior would most likely be the installation of:
- rough plumbing.
- finish flooring.
- fiberglass or other insulation.
- drywall or paneling.
Answer to question 35
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0020) After a house has been framed, the interior of the walls eventually are filled with insulation and covered with drywall or other material. Before this is done, while the spaces between the studs are still open and accessible, the rough plumbing and wiring must be installed. Rough plumbing consists of all the pipes that run within the walls and connect the water source and water heater to the toilets, sinks, washing machines and other elements of the finish plumbing.
Correct Response: A. (Objective 0020) After a house has been framed, the interior of the walls eventually are filled with insulation and covered with drywall or other material. Before this is done, while the spaces between the studs are still open and accessible, the rough plumbing and wiring must be installed. Rough plumbing consists of all the pipes that run within the walls and connect the water source and water heater to the toilets, sinks, washing machines and other elements of the finish plumbing.
Question 36
36. Damage to the local environment during construction of a large office building is most likely to take place during which of the following construction phases?
- framing
- interior finishing
- site preparation
- landscaping
Answer to question 36
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: C. (Objective 0020) Site preparation for a large office building would generally involve considerable digging and moving of many tons of earth. The site itself would generally be uncovered and exposed to the elements. Both factors make surrounding bodies of waters such as streams or lakes vulnerable to pollution due to silting. Erecting the building, finishing the interior, and landscaping can also cause local environmental damage, but the effects of these activities are more easily prevented or mitigated.
Correct Response: C. (Objective 0020) Site preparation for a large office building would generally involve considerable digging and moving of many tons of earth. The site itself would generally be uncovered and exposed to the elements. Both factors make surrounding bodies of waters such as streams or lakes vulnerable to pollution due to silting. Erecting the building, finishing the interior, and landscaping can also cause local environmental damage, but the effects of these activities are more easily prevented or mitigated.
Question 37
37. Modern Portland cement, which is used in concrete and other construction materials, is made by combining several different raw materials that contain calcium, silicon, aluminum, and iron. These raw materials are combined in an extremely hot kiln. Which of the following is the most common source of silicon for making Portland cement?
- clay
- limestone
- quartz
- aragonite
Answer to question 37
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0020) Clay is the most common source of silicon for making Portland cement. Because clay already exists as fine particles, it does not have to be ground before it is combined with the other ingredients. While quartz does contain silicon, it does not react even at the high temperatures of a cement kiln, and so it cannot be used. Limestone and aragonite are good sources for calcium, but not for silicon.
Correct Response: A. (Objective 0020) Clay is the most common source of silicon for making Portland cement. Because clay already exists as fine particles, it does not have to be ground before it is combined with the other ingredients. While quartz does contain silicon, it does not react even at the high temperatures of a cement kiln, and so it cannot be used. Limestone and aragonite are good sources for calcium, but not for silicon.
Question 38
38. Which of the following best explains why concrete foundations and walls are usually reinforced with steel rebar or similar material?
- Concrete is strong in compression but lacks tensile strength.
- Steel rebar substitutes for aggregate in binding cement particles.
- Concrete is brittle and prone to cracking in compression.
- Steel rebar prevents slumping while concrete is plastic before curing.
Answer to question 38
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: A. (Objective 0021) Most concrete walls or other structures are reinforced with metal rods (rebar), steel mesh, or similar materials. Concrete is extremely strong and can bear great loads in compression. However, any force that produces a horizontal as well as a vertical vector will also produce tension in the concrete. Concrete is much less resistant to tensile forces and is prone to cracking under such forces. Metal rebar or similar material reinforces concrete to be better able to withstand these tensile forces.
Correct Response: A. (Objective 0021) Most concrete walls or other structures are reinforced with metal rods (rebar), steel mesh, or similar materials. Concrete is extremely strong and can bear great loads in compression. However, any force that produces a horizontal as well as a vertical vector will also produce tension in the concrete. Concrete is much less resistant to tensile forces and is prone to cracking under such forces. Metal rebar or similar material reinforces concrete to be better able to withstand these tensile forces.
Question 39
39. Which of the following best explains how arches differ from stone or concrete beams or lintels in supporting the load of a bridge across an open space?
- Arches exert an upward force on the bridge that counteracts some of the downward force of the bridge's weight.
- Arches resolve tensile stresses into compressive stresses that can better be supported by stone or concrete.
- Arches reduce the total weight of the bridge by eliminating some of the material that makes up the bridge.
- Arches transmit the weight of the bridge throughout the structure so all points are equally stressed.
Answer to question 39
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0021) Concrete and stone are much stronger in resisting compression than they are in resisting tensile forces. The weight of a structure on a beam or lintel produces a downward force that tends to bend the beam in the middle. This produces compressive force on one side and tensile force on the other. Arches transmit the downward force of the weight of the bridge through the keystone and to the stones on either side as compression, thus eliminating tensile stresses. The compressive forces tend to drive the sides of the arch in opposite directions. Large pillars or buttresses are required to withstand these forces.
Correct Response: B. (Objective 0021) Concrete and stone are much stronger in resisting compression than they are in resisting tensile forces. The weight of a structure on a beam or lintel produces a downward force that tends to bend the beam in the middle. This produces compressive force on one side and tensile force on the other. Arches transmit the downward force of the weight of the bridge through the keystone and to the stones on either side as compression, thus eliminating tensile stresses. The compressive forces tend to drive the sides of the arch in opposite directions. Large pillars or buttresses are required to withstand these forces.
Question 40
40. A house builder has access to a forest of tall, thin softwood trees and a sawmill. The builder chooses a method of framing that would require such resources. Which of the following types of framing would most likely fit this description?
- platform framing
- balloon framing
- timber framing
- braced framing
Answer to question 40
- Answer Enter to expand or collapse answer. Answer expanded
- Correct Response: B. (Objective 0021) Balloon framing includes an outer wall supported by long thin studs that run from the bottom sill all the way to the top of the house. These studs span two or more stories. This method requires access to long lengths of lumber; hence, it has lost popularity as local forests have been depleted.
Correct Response: B. (Objective 0021) Balloon framing includes an outer wall supported by long thin studs that run from the bottom sill all the way to the top of the house. These studs span two or more stories. This method requires access to long lengths of lumber; hence, it has lost popularity as local forests have been depleted.