EEI POSS Practice Questions (2026) — Free Sample Questions with Answers

13 free EEI POSS questions from our 150-question bank, grouped by content domain. Each answer explains why the right option is right — and why every wrong option is wrong.

Reading Comprehension (2)Mechanical Concepts (5)Mathematical Usage (3)Figural Reasoning (3)

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Reading Comprehension

Question 1

Vacuum falls on a hot summer day while hotwell level and air removal are normal. Based on the passage, what is the most likely cause?

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Answer: D

Air is blanketing the condenser tubes.: Ruled out: air removal is normal, so air is not building up around the tubes.

Condensate is covering the lower tubes.: Ruled out: the hotwell level is normal, so no tubes are covered.

The turbine is making more power than usual.: Reverses paragraph 2 and 5: poor vacuum cuts output; it is not caused by extra output.

Warm cooling water is removing less heat.: Correct. Paragraph 4 lists "warm cooling water in summer" as a cause of lost vacuum, and the other causes have been ruled out.

Use the readings to rule causes out: with air removal and hotwell level normal, the remaining cause from the passage is poor heat removal by warm cooling water.

Question 2

Which title best expresses the main idea of the passage?

Entering a Confined Space Safely

¹A confined space is an area large enough for a worker to enter but with limited ways in and out, and it is not designed for anyone to stay inside for long. In a power plant, examples include storage tanks, sumps, large ducts, pipe tunnels and the water boxes of heat exchangers. The danger in these spaces is often invisible. Air that looks clear and smells normal may lack enough oxygen to keep a person conscious, or it may hold a toxic or flammable gas.

²Before anyone enters, the space must be isolated from everything that could flow into it or move inside it. Pumps and agitators are locked out, connecting lines are blanked or disconnected, and the space is drained. A blower then pushes clean outside air into the space. Ventilation controls the hazard, but it does not remove the source, so the air is tested before entry and checked again while work goes on.

³Testing follows a set order. Oxygen is measured first, because the instruments that detect flammable gas need enough oxygen to give a correct reading. Flammable gases and vapors are checked next, since a fire or explosion is usually the most immediate threat. Toxic gases are checked last. Gases inside a space can also stratify. A gas heavier than air settles near the floor, while a lighter one collects near the top, so the tester samples at several levels on the way down rather than only at the opening.

⁴Every entry has an entrant, an attendant and an entry supervisor. The attendant stays outside the space for the whole job, keeps an accurate count of who is inside, stays in contact with the entrants, and orders everyone out if conditions change. The attendant does not go in to attempt a rescue unless trained and equipped for rescue and relieved by another attendant. Many people killed in confined spaces were would-be rescuers who rushed in after a coworker had collapsed.

⁵For this reason, each entrant wears a harness connected by a line to a winch or fixed point outside. If an entrant is overcome, the attendant can pull the person out without entering. The entry permit is posted at the opening. When the work is finished, or when a condition the permit does not allow appears, the supervisor ends the entry and cancels the permit.

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Answer: D

Why Heavier Gases Settle Near the Floor of Tanks: Too narrow: layering is one detail in paragraph 3.

Training Rescue Teams for Plant Tanks: Rescue teams are only mentioned in passing in paragraph 4; the passage is about controlling entry.

How Ventilation Removes Every Hazard: The misconception the passage corrects: paragraph 2 says ventilation "does not remove the source."

How Confined Space Entries Are Controlled: Correct. The passage covers the whole entry process: isolating and ventilating (paragraph 2), testing (3), the roles of each person (4), and retrieval and the permit (5).

A best-title answer must cover every paragraph; options that match only one detail are too narrow.

Mechanical Concepts

Question 3

The pinion turns clockwise on a fixed shaft and meshes with the inside teeth of the ring gear. In which direction does the ring gear turn?

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Answer: A

Clockwise: Correct. Teeth that mesh on the inside of a ring move together at the contact point, so an internal gear turns the same way as the pinion inside it: clockwise.

Counterclockwise: Applied the outside-gear rule; two gears meshed on their outer edges reverse direction, but a pinion inside a ring gear does not.

It will not turn: The ring gear is free to turn and only one pinion drives it, so nothing locks it.

Two external gears turn in opposite directions; a pinion and the internal ring gear it meshes with turn in the same direction.

Question 4

The skid holds a 600 lb motor and a 200 lb pump, 4 ft apart. Ignoring the skid’s weight, from which lifting eye will it hang level?

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Answer: A

1. Total weight = 600 + 200 = 800 lb
2. Distance of centre of gravity from motor = (200 × 4) ÷ 800 = 1 ft
3. Eye A is 1 ft from the motor, so A

Eye A: Correct. The centre of gravity is 200 × 4 ÷ 800 = 1 ft from the motor. Eye A is 1 ft from the motor, directly above that point, so the skid hangs level from it.

Eye B: Eye B is midway between the loads; that would hang level only if the motor and pump weighed the same, so the motor end would drop.

Eye C: Eye C is nearer the lighter pump; the heavy motor end would swing down.

A load hangs level from one hook only when the hook is directly above its centre of gravity, which lies nearer the heavier part.

Question 5

Water is heated in the three vessels shown. In which vessel will the water boil at the lowest temperature?

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Answer: C

Vessel A: Open to the air, water boils at about 212°F, which is higher than under a vacuum.

Vessel B: Reversed: raising the pressure raises the boiling point, so the drum boils at the highest temperature.

Vessel C: Correct. The boiling point rises with pressure and falls as pressure drops. Vessel C is below atmospheric pressure, so its water boils at the lowest temperature.

Water boils at a lower temperature under vacuum and a higher temperature under pressure.

Question 6

A full hose joins Tank A, on a platform, to Tank B. Both water surfaces are at the same height. Which way will water flow?

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Answer: C

From Tank A to Tank B: Tank A sits higher, but a siphon is driven by the difference in surface levels, not by where the tanks sit.

From Tank B to Tank A: Tank B holds more water, but the amount of water does not drive a siphon; the surfaces are level.

It will not flow: Correct. A siphon moves water from the higher liquid surface to the lower one. With both surfaces at the same height there is no difference in level, so no water flows.

A filled siphon flows only while one liquid surface is higher than the other, and it stops when the surfaces are level.

Question 7

Oil at 800 psi can go to either port of the damper cylinder. Oil at which port makes the rod's force greater? (If equal, mark C.)

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Answer: B

Port A: Port A feeds the rod side, where the rod covers part of the piston face, so less area is pushed.

Port B: Correct. Force = pressure × area. Oil at Port B acts on the full piston face, while on the Port A side the thick rod takes up part of the face, so Port B gives more force.

Equal at either port: Ignores that the rod side has less piston area; equal pressure does not mean equal force.

At equal pressure, a cylinder pushes harder extending than retracting, because the rod side has less effective piston area.

Mathematical Usage

Question 8

The floor of a round tank is 10 feet across. What is its area in square feet? [Area of a circle = 3.14 × r², where r = ½ of the distance across]

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Answer: C

1. r = 10 ÷ 2 = 5 feet
2. r² = 25
3. 3.14 × 25 = 78.5 square feet

15.7: Used 3.14 × r without squaring the radius.

31.4: Used 3.14 × the diameter, the circumference formula.

78.5: Correct. r = 10 ÷ 2 = 5 feet, so the area is 3.14 × 5 × 5 = 78.5 square feet.

314.0: Squared the full 10 feet instead of the 5-foot radius.

N (not given): Not the answer: 78.5 appears among the choices.

Halve the distance across to get the radius before squaring.

Question 9

2(X + 3) = 18. X = ?

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Answer: A

1. 2(X + 3) = 18 → X + 3 = 18 ÷ 2 = 9
2. X = 9 − 3 = 6

6.0: Correct. Divide both sides by 2 to get X + 3 = 9, so X = 9 − 3 = 6.

7.5: Did not distribute the 2: solved 2X + 3 = 18.

9.0: Divided by 2 but ignored the + 3.

12.0: Sign error: added 3 instead of subtracting (18 ÷ 2 + 3).

N (not given): Not the answer: 6.0 appears among the choices.

The 2 multiplies everything in the parentheses; divide it out (or distribute it) before isolating X.

Question 10

If C = (F − 32) ÷ 1.8, then F = ?

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Answer: A

1. C = (F − 32) ÷ 1.8
2. Multiply both sides by 1.8: 1.8 × C = F − 32
3. Add 32 to both sides: F = 1.8 × C + 32

1.8 × C + 32: Correct. Multiply both sides by 1.8 to get 1.8 × C = F − 32, then add 32: F = 1.8 × C + 32.

1.8 × C − 32: Kept the minus sign; undoing "− 32" requires adding 32.

(C + 32) ÷ 1.8: Undid the steps in the wrong order and divided instead of multiplying.

(C − 32) × 1.8: Subtracted 32 before multiplying and kept the wrong sign.

N (not given): Not the answer: the correct rearrangement appears among the choices.

Undo operations in reverse order: the last thing done to F (dividing by 1.8) is undone first.

Figural Reasoning

Question 11

Which picture belongs in the empty space?

Picture Progression

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Answer: E

1. Across rows: dot TL → TR → BR.
2. Down columns: arrow up → up-right → right (45° clockwise each row).
3. Missing cell: dot bottom-right, arrow right → E

A: Dot correct, but the arrow points up-right; that is the middle row's direction.

B: Arrow correct, but the dot moved one corner too far, to the bottom-left.

C: Arrow correct, but the dot is in the top-right; that is the middle column's corner.

D: Dot correct, but the arrow points down; it turned 90° per row instead of 45°.

E: Correct. Across each row the dot moves one corner clockwise (top-left, top-right, bottom-right). Down each column the arrow turns 45° clockwise (up, up-right, right). The missing cell has the dot in the bottom-right and the arrow pointing right: E.

When the row and column rules act on different elements, settle each element from its own direction of the grid.

Question 12

Which picture is related to the bottom picture in the same way the two top pictures are related?

Picture Comparison

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Answer: B

1. Top pair: dot top-left → top-right and line right → down; everything turns 90° clockwise.
2. Bottom: dot at top, square at left.
3. Turn 90° clockwise: top → right, left → top, so dot right, square top → B

A: Dot moved correctly, but the square went to the bottom; it was turned the wrong way.

B: Correct. The whole top figure turns 90° clockwise: the dot goes from top-left to top-right and the line from pointing right to pointing down. Turning the bottom circle the same way moves the dot from the top to the right and the small square from the left to the top: B.

C: Turned 90° counterclockwise: the dot went left and the square went to the bottom.

D: Turned 180°: the dot went to the bottom and the square to the right.

E: Mirrored left to right: the dot stayed at the top and the square moved to the right.

When a whole figure turns, every part moves around the centre by the same angle in the same direction.

Question 13

Which picture should come next in the series?

Picture Series

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Answer: C

1. Dot: TL → TR → BR → BL, clockwise one corner, so next is TL.
2. Arrow: up → left → down → right, 90° counterclockwise each step, so next is up.
3. Next: dot top-left, arrow up → C

A: Dot correct, but the arrow still points right; it did not turn.

B: Arrow correct, but the dot is in the top-right; it moved two corners.

C: Correct. The dot moves one corner clockwise each step (top-left, top-right, bottom-right, bottom-left), so it returns to the top-left. The arrow turns 90° counterclockwise each step (up, left, down, right), so it points up again. C has both.

D: Arrow correct, but the dot stayed in the bottom-left corner.

E: Dot correct, but the arrow points down; it turned clockwise instead of counterclockwise.

Two elements can move in opposite rotational directions; check the direction of each one separately.

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