10 Free 2A Practice Questions (Printable)

10 free 2A practice questions (printable)

Ten original exam-style 2nd Class Part A (2A) questions from our free public sample, written to the public syllabus. Work them on paper, then check the answer key at the end. They are not questions from a real exam, and a score here does not predict your exam result.

1. Using ASME Section I (PG-27.2.1), calculate the minimum required wall thickness of a strength-welded watertube boiler tube of 70 mm O.D. The maximum allowable working pressure is 4 MPag, the maximum allowable stress S = 87.8 MPa, the weld strength reduction factor w = 1.0, and the thickness factor e = 0 (strength welded).

A. 1.9 mm
B. 3.5 mm
C. 2.3 mm
D. 1.6 mm

Question ID 2A1-C01-Q001 · Unit §1: ASME Code, Sections I & VIII, Calculations · Report an error

2. Using ASME Section I (PG-52), calculate the longitudinal ligament efficiency for a row of tube holes 63.5 mm in diameter spaced at an equal longitudinal pitch of 116 mm.

A. 0.4474
B. 0.4526
C. 0.6516
D. 0.5474

Question ID 2A1-C01-Q019 · Unit §1: ASME Code, Sections I & VIII, Calculations · Report an error

3. A body moving at 20 m/s accelerates uniformly at 4 m/s² for 5 seconds. What is the total distance travelled during this period?

A. 100 m
B. 150 m
C. 200 m
D. 120 m

Question ID 2A1-C08-Q001 · Unit §3: Applied Mechanics · Report an error

4. On what physical principle does a venturi meter rely to measure flow rate?

A. Flow is found from the temperature drop of the fluid as it passes through the throat
B. Flow is measured by the rise in pressure that accompanies the slowing of fluid at the throat
C. Flow is determined solely from the change in fluid density between the pipe and the throat
D. Flow can be correlated to the drop in pressure caused by the increase in flow velocity at the constricted throat

Question ID 2A1-C12-Q020 · Unit §3: Applied Mechanics · Report an error

5. Using the relationship Q = m c (t2 - t1), calculate the quantity of heat required to raise 1000 litres of fresh water from 10 degrees C to 90 degrees C, given the specific heat of fresh water is 4.183 kJ/kg degrees C and 1 litre of water has a mass of 1 kg.

A. 419 MJ
B. 335 MJ
C. 37.6 MJ
D. 377 MJ

Question ID 2A2-C01-Q001 · Unit §4: Thermodynamics · Report an error

6. Metallurgy is divided into three well-defined groups. Which group is specifically concerned with the study of the structure of metals and how modifying that structure (through composition, alloying, and heat treatment) produces more desirable properties?

A. Pyrometallurgy
B. Extractive metallurgy
C. Mechanical metallurgy
D. Physical metallurgy

Question ID 2A2-C05-Q001 · Unit §5: Metallurgy · Report an error

7. According to the chapter's corrosion characteristics, which corrosion type is caused by a local difference in environment composition (such as oxygen concentration) and afflicts mechanical joints like coupled pipes or threaded connections?

A. Caustic attack (grooving or gouging)
B. Erosion-corrosion
C. Crevice corrosion
D. Galvanic corrosion

Question ID 2A2-C06-Q030 · Unit §6: Testing of Materials · Report an error

8. Under the regulations made under the Boilers Act, one square metre of heating surface is taken to equal 10 kW. A boiler has 92.9 m² of heating surface but is actually developing 975.45 kW. At what percentage of its rating is this boiler operating?

A. 100%
B. 110%
C. 105%
D. 95%

Question ID 2A3-C01-Q001 · Unit §7: Boilers · Report an error

9. According to the chapter, why is ocean water generally unsuitable for most industrial applications even though it is often used for cooling?

A. It has too many dissolved solids
B. It is naturally too acidic for plant piping
C. It is too cold to be effective in heat exchangers
D. It contains too little dissolved oxygen

Question ID 2A3-C06-Q001 · Unit §9: Water Treatment · Report an error

10. According to the chapter, what is the maximum acceptable concentration of E. coli in potable water?

A. 0 per 100 mL
B. 0.3 mg/L
C. 1 per 100 mL
D. 10 per 100 mL

Question ID 2A3-C10-Q021 · Unit §9: Water Treatment · Report an error

Answer key

1. A (2A1-C01-Q001), For tubing up to 125 mm O.D., t = PD/(2Sw + P) + 0.005D + e. The pressure-stress term is (4 x 70)/((2 x 1.0 x 87.8) + 4) = 280/179.6 = 1.56 mm, and 0.005D = 0.005 x 70 = 0.35 mm, giving 1.56 + 0.35 = 1.9 mm. Stopping at 1.56 mm omits the mandatory 0.005D term. Larger results come from dropping the +P in the denominator or mis-scaling the diameter term.
2. B (2A1-C01-Q019), For equal pitch in every row, E = (p - d)/p = (116 - 63.5)/116 = 52.5/116 = 0.4526. Computing d/p instead of (p - d)/p gives 0.5474 (its complement); using a wrong pitch or diameter shifts the value. This longitudinal efficiency is then compared against the diagonal ligament efficiency, and the lesser governs the design.
3. B (2A1-C08-Q001), Final velocity is v = u + at = 20 + (4 × 5) = 40 m/s. Distance is the average velocity times time: s = ((u + v)/2) × t = ((20 + 40)/2) × 5 = 30 × 5 = 150 m. The result of 100 m comes from using only the initial velocity (20 × 5). The 200 m result comes from using only the final velocity (40 × 5). The 120 m result comes from an averaging error.
4. D (2A1-C12-Q020), A venturi meter applies Bernoulli's principle: as the flow speeds up through the narrower throat, the pressure drops, and this measurable pressure drop correlates with the flow rate. Velocity increases (so pressure falls, not rises) at the throat, the fluid is treated as incompressible so density does not change, and the method does not rely on temperature change.
5. B (2A2-C01-Q001), Heat added is the product of mass, specific heat, and temperature rise: 1000 kg x 4.183 kJ/kg degrees C x (90 - 10) = 334 640 kJ, which rounds to about 335 MJ. Multiplying by the full 90 degrees C instead of the 80 degree rise gives the inflated 377 MJ figure; using only a 9 degree difference gives 37.6 MJ; and 419 MJ comes from using 100 degrees C of rise. Only the figure based on the correct 80 degree temperature change is right.
6. D (2A2-C05-Q001), Physical metallurgy is the study of the structure of metals; properties are intimately related to structure, and careful modification of structure (by changing chemical composition, alloys, and heat treatments) yields better properties. Extractive metallurgy deals with extracting and purifying metals from their ores. Mechanical metallurgy studies the techniques and mechanical forces (stress, time, temperature) that shape finished metal forms. Pyrometallurgy is not one of the three groups; it is a single extraction path (melting ore in a furnace).
7. C (2A2-C06-Q030), Crevice corrosion afflicts mechanical joints such as coupled pipes or threaded connections and is triggered by a local difference in environment composition (oxygen concentration), producing localized scale and pitting. Galvanic corrosion is caused by contact of different metals; caustic attack results from salt concentration in high-heat zones producing a wide smooth groove; erosion-corrosion is caused by flowing particles damaging protective films at restrictions and bends.
8. C (2A3-C01-Q001), The rated output is found by multiplying the heating surface by 10 kW/m²: 92.9 × 10 = 929 kW. The actual output of 975.45 kW divided by the 929 kW rating gives 1.05, or 105% of rating. Reading it as 95% reverses the ratio; 100% ignores that the actual output exceeds the rating; 110% overstates the surplus.
9. A (2A3-C06-Q001), Ocean water is often used for cooling water but has too many dissolved solids (such as sodium chloride) to be used for most industrial applications.
10. A (2A3-C10-Q021), E. coli has no non-fecal source, so its presence means the water is definitely contaminated and unsafe to drink. The maximum acceptable concentration of E. coli is 0 per 100 mL of water; if detected, a boil water advisory is issued.

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