Industrial Skills Test (IST) — Questions and Answers

Question 1: Which shape can completely fill a three-dimensional space without gaps when tiled together?

Cone
Cube (Correct answer)
Cylinder
Sphere

Correct answer: Cube

A cube is one of the few three-dimensional shapes that can tessellate, or completely fill, a three-dimensional space without leaving any gaps or overlaps when stacked together. This property is due to its perfectly flat faces and 90-degree angles, allowing for seamless packing in all directions. Other shapes like spheres or cylinders would leave significant gaps.

Question 2: If a cube is painted on all six faces and then cut into smaller cubes, how many of the smaller cubes will have paint on exactly two faces?

32
8
12 (Correct answer)
24

Correct answer: 12

Cubes with paint on exactly two faces are located along the edges of the original large cube, but not at the corners. A cube has 12 edges. If the large cube is cut into a 3x3x3 array of smaller cubes, each edge will have (3-2)=1 smaller cube with paint on exactly two faces. Therefore, 12 edges multiplied by 1 cube per edge equals 12 cubes.

Question 3: What device is used to protect an electrical circuit from damage caused by excess current?

Fuse or circuit breaker (Correct answer)
Capacitor
Relay
Transformer

Correct answer: Fuse or circuit breaker

Fuses and circuit breakers protect circuits by interrupting the flow of current when it exceeds a safe level.

Question 4: A bolt is 3.75 inches long. What is this measurement in fractions of an inch?

3 7/8"
3 1/2"
3 3/4" (Correct answer)
3 5/8"

Correct answer: 3 3/4"

0.75 equals 3/4, so 3.75 inches is 3 and 3/4 inches.

Question 5: In a 3-phase wye-connected system, the phase-to-neutral voltage is 277 V. What is the line-to-line voltage?

208 V
480 V (Correct answer)
554 V
277 V

Correct answer: 480 V

Line voltage in a wye system equals phase voltage times the square root of 3 (277 x 1.732 ≈ 480 V).

Question 6: What is the standard frequency of AC power in the United States?

120 Hz
240 Hz
50 Hz
60 Hz (Correct answer)

Correct answer: 60 Hz

The US power grid operates at 60 Hz, meaning the current alternates direction 60 times per second.

Question 7: A motor turning at 1,750 RPM has a 4-inch pulley that drives an 8-inch pulley. What is the speed of the driven shaft?

1,750 RPM
7,000 RPM
3,500 RPM
875 RPM (Correct answer)

Correct answer: 875 RPM

Driven RPM = Driver RPM × (Driver diameter ÷ Driven diameter) = 1,750 × (4 ÷ 8) = 875 RPM. A larger driven pulley turns more slowly.

Question 8: What does the term 'downtime' refer to in industrial production?

Time when a machine or production line is not operating due to failure or maintenance (Correct answer)
Overtime hours worked during night shifts
The cooling-down period after a machine completes a run
Time when workers are on scheduled break

Correct answer: Time when a machine or production line is not operating due to failure or maintenance

Downtime refers to periods when production equipment is not operational due to breakdowns, maintenance, or other interruptions.

Question 9: Which type of simple machine is a seesaw?

Pulley
Inclined Plane
Lever (Correct answer)
Screw

Correct answer: Lever

A seesaw is a classic example of a lever, specifically a Class 1 lever. It consists of a rigid bar (the board) that pivots around a fixed point called a fulcrum (the central support). The effort force is applied on one side, and the load (the person) is on the other, demonstrating how levers can multiply force or change the direction of motion.

Question 10: If you have a solid block in the shape of a rectangular prism and you remove a smaller rectangular prism from one corner, how many faces will the resulting shape have?

8
10
6
7 (Correct answer)

Correct answer: 7

A rectangular prism initially has 6 faces. When a corner is removed, for example by making a single planar cut (a truncation), one new face is created. The three original faces that met at the corner are reshaped, and the three faces opposite the corner remain untouched. This results in a total of 3 untouched faces + 3 reshaped original faces + 1 new face = 7 faces for the resulting shape.

Question 11: What is the primary function of a dial indicator in industrial work?

To measure small variations in position or surface runout (Correct answer)
To measure electrical current in motors
To calibrate digital measuring instruments
To test the hardness of steel components

Correct answer: To measure small variations in position or surface runout

A dial indicator measures small amounts of movement or variation in position, commonly used for runout, alignment, and deflection checks.

Question 12: What is the primary purpose of the title block in a technical drawing?

To provide part name, material, scale, revision history, and other identifying information (Correct answer)
To list required safety warnings
To indicate which tools are needed to manufacture the part
To show the main orthographic view of the part

Correct answer: To provide part name, material, scale, revision history, and other identifying information

The title block contains essential information including part name, part number, material specification, drawing scale, drafter name, and revision history used to control the document.

Question 13: A 120V outlet is connected to a 1,200W appliance. What current does it draw?

5 A
8 A
10 A (Correct answer)
12 A

Correct answer: 10 A

Current = Power ÷ Voltage = 1,200W ÷ 120V = 10 Amps.

Question 14: What does 'GFCI' stand for and what does it protect against?

Ground Fault Continuity Indicator — tests circuit continuity
Ground Fault Current Indicator — measures leakage current
General Frequency Control Instrument — regulates AC frequency
Ground Fault Circuit Interrupter — protects against ground fault shock (Correct answer)

Correct answer: Ground Fault Circuit Interrupter — protects against ground fault shock

GFCI stands for Ground Fault Circuit Interrupter and protects people from electric shock caused by ground faults.

Question 15: How do you reverse the rotation of a three-phase induction motor?

Add a start capacitor
Swap any two of the three line leads (Correct answer)
Reverse the polarity of the neutral
Swap all three line leads

Correct answer: Swap any two of the three line leads

Interchanging any two supply phases reverses the rotating magnetic field.

Question 16: What is the approximate forward voltage drop across a conducting silicon diode?

5.0 V
0.3 V
0.7 V (Correct answer)
1.5 V

Correct answer: 0.7 V

Silicon diodes typically drop about 0.6 to 0.7 V when forward biased.

Question 17: If a pyramid has a square base and is viewed from above, what shape will be visible?

Square (Correct answer)
Rectangle
Triangle
Hexagon

Correct answer: Square

When a pyramid with a square base is viewed directly from above, the observer looks down onto its base. The apex (the top point) of the pyramid will appear as a central point, and the four triangular faces will converge towards it, but the outermost boundary of what is seen will be the square shape of its base.

Question 18: What is the correct action when a worker discovers a safety hazard that cannot be immediately corrected?

Ignore it if no one has been hurt yet
Report it to a supervisor immediately and isolate the area (Correct answer)
Fix it personally regardless of authorization
Continue working and note it in the next monthly report

Correct answer: Report it to a supervisor immediately and isolate the area

Workers must report hazards immediately to a supervisor so the area can be isolated and the hazard corrected promptly.

Question 19: The passage indicates that cross-training employees in different roles:

Is a waste of resources
Decreases overall job satisfaction
Increases workplace flexibility and productivity (Correct answer)
Is only beneficial in small companies

Correct answer: Increases workplace flexibility and productivity

Cross-training employees means teaching them to perform multiple tasks or roles within the organization. This practice enhances workplace flexibility, as employees can cover for absent colleagues or shift to areas with higher demand. It also boosts overall productivity by creating a more versatile workforce capable of adapting to changing operational needs and reducing bottlenecks.

Question 20: What does the scale notation '1:2' on a technical drawing mean?

The drawing is twice the actual size of the object
Two separate drawings represent one complete part
One inch on the drawing represents two feet in reality
The drawing is half the actual size of the object (Correct answer)

Correct answer: The drawing is half the actual size of the object

A scale of 1:2 means the drawing is drawn at half actual size, so every unit measured on the drawing represents two units on the real object.

Question 21: According to the passage, what is the primary function of a conveyor belt in an industrial setting?

To improve safety standards
To transport materials from one location to another (Correct answer)
To increase employee productivity
To reduce the need for manual labor

Correct answer: To transport materials from one location to another

Conveyor belts are fundamental components in industrial settings, designed specifically for the efficient and continuous movement of goods, products, or raw materials. Their primary role is to automate the transportation process, moving items along a fixed path within a facility. This function streamlines operations and reduces the need for manual carrying.

Question 22: In blueprint reading, what does the abbreviation 'OD' stand for?

Outer Diameter (Correct answer)
Overall Depth
Original Drawing
Object Dimension

Correct answer: Outer Diameter

OD stands for Outer Diameter, which refers to the measurement across the outside of a circular or cylindrical object such as a pipe or shaft.

Question 23: In a confined space, what is the minimum oxygen level considered safe for entry?

16%
21%
19.5% (Correct answer)
18%

Correct answer: 19.5%

OSHA defines an oxygen-deficient atmosphere as below 19.5%, making 19.5% the minimum safe level for confined space entry.

Question 24: What type of line in a technical drawing represents the visible outline or edge of an object?

Centerline (alternating dashes)
Object line (visible line) (Correct answer)
Hidden line (dashed)
Section line

Correct answer: Object line (visible line)

Object lines (visible lines) are solid, thick continuous lines that represent edges and outlines directly visible from the current viewing angle.

Question 25: In the passage, it is mentioned that routine maintenance of machinery can prevent:

Employee turnover
Increased energy consumption
Unexpected breakdowns (Correct answer)
Worker fatigue

Correct answer: Unexpected breakdowns

Routine maintenance is crucial for the longevity and reliability of industrial machinery. By regularly inspecting, servicing, and replacing worn parts, potential issues can be identified and addressed before they escalate. This proactive approach significantly reduces the likelihood of sudden equipment failures, which can cause costly downtime and production delays.

Question 26: A 20-tooth driver gear turning at 900 RPM meshes with a 60-tooth driven gear. What is the speed of the driven gear?

300 RPM (Correct answer)
2,700 RPM
600 RPM
450 RPM

Correct answer: 300 RPM

Driven RPM = 900 x 20 / 60 = 300 RPM.

Question 27: What do dashed lines represent in a technical drawing?

Dimension reference lines
Cutting plane locations
The axis of symmetry of a cylindrical feature
Edges or features hidden behind a visible surface (Correct answer)

Correct answer: Edges or features hidden behind a visible surface

Dashed lines (hidden lines) represent edges or features that exist behind the visible surface and cannot be seen from the current viewing angle.

Question 28: Which three-dimensional shape will you get if you rotate a rectangle around one of its sides?

Sphere
Cone
Pyramid
Cylinder (Correct answer)

Correct answer: Cylinder

When a rectangle is rotated around one of its sides, that side becomes the axis of rotation. The opposite side sweeps out a circular path, forming the top and bottom circular bases of the resulting three-dimensional shape. The other two sides of the rectangle trace out the curved lateral surface, thus creating a cylinder.

Question 29: What is the main idea of the passage regarding energy efficiency in factories?

Training employees on energy conservation is unnecessary
Implementing energy-efficient technologies can reduce operational costs (Correct answer)
Factories should focus on hiring skilled workers
Energy efficiency has no significant impact on production

Correct answer: Implementing energy-efficient technologies can reduce operational costs

Energy efficiency in factories focuses on optimizing energy consumption to perform the same tasks with less power. By adopting technologies like LED lighting, efficient motors, and improved insulation, factories can significantly lower their utility bills. This reduction in energy expenditure directly translates into substantial savings on operational costs, improving the company's financial performance.

Question 30: A machine uses 15 gallons of coolant per day. How many gallons are needed for a 5-day work week?

75 gallons (Correct answer)
80 gallons
70 gallons
60 gallons

Correct answer: 75 gallons

Multiplying 15 gallons/day by 5 days equals 75 gallons.

Question 31: What happens to the inductive reactance of a coil when the supply frequency increases?

It increases (Correct answer)
It drops to zero
It stays the same
It decreases

Correct answer: It increases

XL = 2πfL, so reactance is directly proportional to frequency.

Industrial Skills Test (IST)

The IST is an industrial aptitude assessment used by employers to evaluate candidates for skilled trade, manufacturing, and utility positions across reading comprehension, applied mathematics, electrical knowledge, and spatial reasoning.

Questions

80 min

Time Limit

70%

To Pass

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

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