2A sample questions, explained
6 questions from our free public 2A sample, with the answer, a worked explanation, and why each other option is not the answer. They are original exam-style questions written to the public syllabus, not questions from a real exam. Print 10 free 2A questions.
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
Show the answer and explanation
Answer: A. 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.
Why the other options are not the answer
- B. 3.5 mm is far too large; it comes from mis-applying the formula, for example dropping +P from the denominator or mis-scaling the diameter term.
- C. 2.3 mm does not follow from PD/(2Sw + P) + 0.005D + e with the given values.
- D. 1.6 mm stops at the pressure-stress term (1.56 mm) and leaves out the mandatory 0.005D allowance.
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
Show the answer and explanation
Answer: B. 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.
Why the other options are not the answer
- A. 0.4474 comes from using a wrong pitch or diameter in (p − d)/p.
- C. 0.6516 comes from using a wrong pitch or diameter in (p − d)/p.
- D. 0.5474 is d/p (63.5/116), the complement of the ligament efficiency.
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
Show the answer and explanation
Answer: B. 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.
Why the other options are not the answer
- A. 100 m uses only the initial velocity (20 m/s × 5 s).
- C. 200 m uses only the final velocity (40 m/s × 5 s).
- D. 120 m comes from an averaging error; the average velocity is (20 + 40)/2 = 30 m/s.
Question ID 2A1-C08-Q001 · Unit §3: Applied Mechanics · Report an error
4. 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
Show the answer and explanation
Answer: B. 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.
Why the other options are not the answer
- A. 419 MJ comes from a 100-degree rise instead of 80.
- C. 37.6 MJ uses only a 9-degree rise.
- D. 377 MJ uses the full 90 °C instead of the 80 °C rise.
Question ID 2A2-C01-Q001 · Unit §4: Thermodynamics · Report an error
5. 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
Show the answer and explanation
Answer: D. 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).
Why the other options are not the answer
- A. Pyrometallurgy is not one of the three groups; it is one extraction route (smelting ore in a furnace).
- B. Extractive metallurgy deals with getting metals out of their ores and purifying them.
- C. Mechanical metallurgy studies the forces and techniques that shape metal into finished forms.
Question ID 2A2-C05-Q001 · Unit §5: Metallurgy · Report an error
6. 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%
Show the answer and explanation
Answer: C. 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.
Why the other options are not the answer
- A. 100% ignores that the actual output (975.45 kW) exceeds the 929 kW rating.
- B. 110% overstates the surplus; 975.45 ÷ 929 = 1.05.
- D. 95% reverses the ratio (929 ÷ 975.45).
Question ID 2A3-C01-Q001 · Unit §7: Boilers · Report an error
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