Free Practice Questions for Sri Lanka Engineering Service Exam

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Sample Sri Lanka Engineering Service Exam Practice Questions

Try these sample questions to review concepts for the Sri Lanka Engineering Service Exam exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A simply supported beam of span L carries a uniformly distributed load of w (kN/m) across its entire length. What is the magnitude and location of the maximum bending moment?

A.wL²/4 at the midspan (L/2)

B.wL²/8 at the midspan (L/2)

C.wL²/12 at the supports

D.wL²/2 at the quarter-span (L/4)

Explanation: For a simply supported beam with a uniformly distributed load w over span L, the vertical reaction at each support is wL/2. Setting up the bending moment equation at distance x from one support yields M(x) = (wL/2)x - w x²/2. Differentiating with respect to x and setting the shear force to zero gives x = L/2, where the maximum bending moment evaluates to M_max = (wL/2)(L/2) - (w/2)(L/2)² = wL²/8.

2According to Hooke's Law for linearly elastic isotropic materials, what is the formula for the axial elongation (ΔL) of a prismatic bar with cross-sectional area A and length L subjected to an axial tensile force P?

A.ΔL = PL² / (2AE)

B.ΔL = AE / (PL)

C.ΔL = P / (AEL)

D.ΔL = PL / (AE)

Explanation: Normal axial stress is defined as σ = P/A and normal axial strain is ε = ΔL/L. Under Hooke's law in the linear elastic range, σ = Eε. Substituting the expressions for stress and strain yields P/A = E(ΔL/L), which rearranges directly to ΔL = PL / (AE), where AE represents the axial rigidity of the member.

3In structural column design, how is the slenderness ratio (λ) of a compression member defined?

A.Effective length divided by the least radius of gyration (Leff / r_min)

B.Total length divided by the cross-sectional area (L / A)

C.Least lateral dimension divided by the effective length (d_min / Leff)

D.Effective length divided by the second moment of area (Leff / I)

Explanation: The slenderness ratio λ of a column is defined as the ratio of its effective buckling length Leff to its least radius of gyration r_min, where r = √(I/A). This dimensionless parameter governs the buckling susceptibility and determines whether a column fails predominantly by material yielding (short column) or elastic/inelastic flexural buckling (slender column).

4A simply supported rectangular timber beam of span 4 m carries a central concentrated load of 12 kN. The beam cross-section has width b = 100 mm and depth d = 200 mm. Ignoring self-weight, what is the maximum bending stress in the beam?

A.36.0 MPa

B.9.0 MPa

C.18.0 MPa

D.12.0 MPa

Explanation: First, the maximum bending moment for a simply supported beam with a central point load is M = PL/4 = (12 kN × 4 m) / 4 = 12 kNm = 12 × 10⁶ N·mm. The elastic section modulus of a rectangular section is Z = bd²/6 = (100 mm × (200 mm)²)/6 = (100 × 40,000)/6 = 666,667 mm³. The maximum flexural stress is σ = M / Z = (12 × 10⁶ N·mm) / (666,667 mm³) = 18.0 N/mm² = 18.0 MPa.

5An ideal steel column of length L = 3.0 m has pinned ends (K = 1.0). The modulus of elasticity is E = 200 GPa and the least second moment of area is I = 4.5 × 10⁻⁶ m⁴. What is the Euler critical buckling load (P_cr) of this column?

A.3,948 kN

B.493 kN

C.1,974 kN

D.987 kN

Explanation: Euler's critical buckling load for a pin-ended column is P_cr = π²EI / L². Substituting the given values: P_cr = π² × (200 × 10⁹ N/m²) × (4.5 × 10⁻⁶ m⁴) / (3.0 m)² = π² × 900,000 / 9 = 100,000 π² N ≈ 100,000 × 9.8696 N = 986,960 N ≈ 987 kN.

6In reinforced concrete design conforming to limit state principles, why do standard building codes deliberately require flexural members to be designed as under-reinforced sections?

A.To prevent shear cracks from developing in the tension zone near the beam supports

B.To ensure tensile steel yields before concrete reaches its ultimate compressive strain, providing ductile failure with visible warning

C.To maximize the moment capacity of the beam for a given cross-sectional concrete area

D.To eliminate the need for secondary shear stirrups and compression reinforcement

Explanation: In an under-reinforced concrete section, the tension steel reinforcement reaches its yield point well before the concrete in the compression zone reaches its ultimate compressive crushing strain (typically 0.0035). As the steel yields, large cracks open on the tension face and significant deflections occur, giving occupants ample visible warning of impending failure before final collapse.

7For a beam with a solid rectangular cross-section of width b and depth d subjected to a vertical shear force V, what is the maximum transverse shear stress (τ_max) and where does it occur?

A.1.33 × (V / bd) at the extreme top fibers

B.1.0 × (V / bd) at the neutral axis

C.1.5 × (V / bd) at the neutral axis

D.2.0 × (V / bd) at the extreme bottom fibers

Explanation: Transverse shear stress across a beam section is given by Jourawski's formula τ = VQ / (Ib). For a rectangular section, Q is maximized at the neutral axis (y = 0) where Q = (b·d/2)(d/4) = bd²/8. With I = bd³/12, τ_max = V(bd²/8) / [(bd³/12)b] = (3/2)(V / bd) = 1.5 τ_avg. Shear stress is parabolic, zero at extreme top and bottom fibers, and maximum at the neutral axis.

8A uniform beam of span L is built-in (fixed) at both ends and carries a total uniformly distributed load of w (kN/m). What are the magnitudes of the hogging bending moment at the supports and the sagging bending moment at midspan?

A.Support moment = wL²/12; Midspan moment = wL²/24

B.Support moment = wL²/8; Midspan moment = wL²/8

C.Support moment = wL²/16; Midspan moment = wL²/16

D.Support moment = wL²/24; Midspan moment = wL²/12

Explanation: For a beam fixed at both ends under a uniform load w, the fixed-end hogging moment at the supports is M_supp = wL²/12. The total free bending moment for a simply supported beam of the same span is wL²/8. The sagging moment at midspan is therefore M_mid = wL²/8 - wL²/12 = wL²/24. The support moment is twice as large as the midspan moment.

9A cantilever beam of length L = 3.0 m carries a concentrated downward load P = 15 kN at its free tip. The flexural rigidity of the beam is EI = 15,000 kN·m². What is the maximum vertical deflection at the free end?

A.27.0 mm

B.4.5 mm

C.18.0 mm

D.9.0 mm

Explanation: The tip deflection of a cantilever beam carrying an end point load P is given by the standard formula δ = PL³ / (3EI). Substituting the given values: δ = [15 kN × (3.0 m)³] / [3 × 15,000 kN·m²] = (15 × 27) / 45,000 = 405 / 45,000 = 0.009 m = 9.0 mm.

10A plane pin-jointed truss has m members, j joints, and r reaction components at the supports. What is the expression for the degree of static indeterminacy (D_s), and what does D_s < 0 indicate?

A.D_s = 2m + r - j; D_s < 0 indicates the truss is internally redundant

B.D_s = m + r - 2j; D_s < 0 indicates the truss is statically unstable (a mechanism)

C.D_s = m + 2r - 3j; D_s < 0 indicates the truss has zero-force members

D.D_s = 3m + r - 3j; D_s < 0 indicates the truss is externally indeterminate

Explanation: In a 2D pin-jointed truss, each joint provides 2 independent static equilibrium equations (ΣFx = 0, ΣFy = 0). For j joints, there are 2j equations. The total number of unknowns is the number of bar forces m plus reaction components r. The degree of static indeterminacy is D_s = m + r - 2j. If D_s = 0 the truss is determinate; if D_s > 0 it is indeterminate; if D_s < 0 it lacks sufficient members or restraints and forms an unstable mechanism.

About the Sri Lanka Engineering Service Exam Exam

The Open Competitive Examination for Recruitment of Officers to Grade III of the Sri Lanka Engineering Service selects registered graduate engineers for island-wide public service technical posts under the Civil, Mechanical, Electrical, Chemical and Earth Resources categories. The official paper is a single 100-mark multiple-choice aptitude test that probes critical reasoning, analytical power and decision-making grounded in the engineering science a four-year B.Sc. Engineering degree covers.

Exam sponsor: Held on the order of the Public Service Commission. The written paper for the 2020 and 2024 open cycles was conducted by the Director General of the Sri Lanka Institute of Development Administration (SLIDA), and applications were submitted online at www.slida.lk.. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

A single written aptitude examination of 100 marks, all multiple-choice, lasting 1.5 hours, designed to measure critical reasoning, analytical power and decision-making based on the knowledge gained from the candidate's engineering science studies. Candidates are then called for an interview in order of written marks; the interview verifies physical fitness and qualifications and carries no marks. Recruitment categories are Civil, Mechanical, Electrical, Chemical and Earth Resources.

Time Limit

1.5 hours (90 minutes).

Passing Score

No pass mark is published. Selection is strictly by the order of marks at the written examination, up to the number of vacancies gazetted for each category; the interview carries no marks.

Exam / Certification Fees

Rs. 1,000.00 for the 2024 open cycle, paid at any People's Bank branch in favour of the Secretary, Ministry of Public Administration, Provincial Councils and Local Government. The fee is not refunded.

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

10%

Structural Analysis and Mechanics of Materials

Stress-strain behavior, bending moment, shear force, beam deflection, column buckling, and concrete/steel design fundamentals.

10%

Fluid Mechanics and Hydraulics

Hydrostatics, Bernoulli equation, pipe friction, open-channel flow, Manning's equation, hydraulic structures, and pumps.

10%

Geotechnical and Foundation Engineering

Soil classification, effective stress, compaction, permeability, shear strength, bearing capacity, and retaining walls.

10%

Highway, Transportation and Surveying

Geometric design, stopping sight distance, pavement layers, traffic flow, leveling, total station geomatics, and earthwork volumes.

10%

Construction Materials and Concrete Technology

Portland cement hydration, concrete mix design, water-cement ratio, aggregates, curing, and non-destructive testing.

10%

Environmental Engineering and Hydrology

Water and wastewater treatment, BOD5 calculations, runoff estimation via Rational method, EIA procedures, and solid waste.

10%

Electrical Systems and Building Services

Three-phase power, circuit laws, transformers, electric motors, earthing, building electrical protection, and backup power.

10%

Mechanical Engineering and Equipment Management

Thermodynamics, heat transfer, construction machinery productivity, pump hydraulic power, and equipment operating cycles.

10%

Project Management, Estimation and Procurement

Critical Path Method (CPM), PERT, Earned Value Management, BOQ preparation, and Sri Lanka CIDA contract and Government Procurement Guidelines practice.

10%

Engineering Ethics, Safety and Statutory Regulations

Engineering Council, Sri Lanka Act No. 4 of 2017, IESL Code of Ethics, Factories Ordinance safety duties, and disaster-risk clearances.

Preparing for the Sri Lanka Engineering Service Exam Exam

What You Need to Know

Passing score: No pass mark is published. Selection is strictly by the order of marks at the written examination, up to the number of vacancies gazetted for each category; the interview carries no marks.
Assessment: A single written aptitude examination of 100 marks, all multiple-choice, lasting 1.5 hours, designed to measure critical reasoning, analytical power and decision-making based on the knowledge gained from the candidate's engineering science studies. Candidates are then called for an interview in order of written marks; the interview verifies physical fitness and qualifications and carries no marks. Recruitment categories are Civil, Mechanical, Electrical, Chemical and Earth Resources.
Time limit: 1.5 hours (90 minutes).
Exam / certification fees: Rs. 1,000.00 for the 2024 open cycle, paid at any People's Bank branch in favour of the Secretary, Ministry of Public Administration, Provincial Councils and Local Government. The fee is not refunded. Official sources

Using Our Practice Resources

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Sri Lanka Engineering Service Exam: Suggested Study Strategy

1Practise fast, accurate engineering-science reasoning under time pressure: the official paper allots only 1.5 hours for a 100-mark multiple-choice test in which every question must be answered, so pace matters as much as depth.

2Rebuild fluency in the core quantitative methods of your recruitment category (Civil, Mechanical, Electrical, Chemical or Earth Resources), including beam and column formulae, pipe and open-channel hydraulics, effective stress, and three-phase power.

3Review Sri Lankan professional and statutory context you already need for ECSL registration: the Engineering Council, Sri Lanka Act No. 4 of 2017, the IESL Code of Ethics, Factories Ordinance safety duties, National Environmental Act licensing, and Government Procurement Guidelines.

Frequently Asked Questions

Who is eligible to sit for the SLES open competitive examination?

Applicants must be Sri Lankan citizens aged 21 to 35 at the closing date (45 for a confirmed public officer who meets PSC Circular No. 01/2020), hold a full-time four-year B.Sc. Engineering degree recognised by the University Grants Commission and IESL, and be registered with the Engineering Council, Sri Lanka as an Associate or Chartered Engineer with the matching IESL membership.

What is the examination structure and medium?

Schedule II of the Service Minute limits the written examination to one aptitude paper of 100 marks, made up entirely of multiple-choice questions and lasting 1.5 hours. It is held in Sinhala, Tamil and English, and candidates sit in one language of their choice, which cannot be changed after applying. An interview follows to verify physical fitness and qualifications, and it carries no marks.

How are candidates selected for appointment to SLES Grade III?

Selection is strictly by rank order of the marks obtained at the written examination, up to the number of vacancies gazetted for each recruitment category. No pass mark is published, and the interview awards no marks. Where tied marks exceed the remaining vacancies, PSC Circular No. 01/2024 allows an additional written examination and a competency-based interview for those candidates only.

Is this question bank an official SLES paper or a simulation of it?

No. These are independent practice questions written by OpenExamPrep in English to help you revise engineering science, quantitative problem-solving and Sri Lankan statutory practice. They are not official, recalled, or SLIDA-supplied items, and the coverage and difficulty will differ from the real 100-mark aptitude paper, which itself is offered in Sinhala, Tamil and English.