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Key Facts: Engineer Electricity Exam

100 items

Official written exam paper length (5 subjects × 20)

Q-Net Engineer-grade testing standards; Q-Net 전기기사 (jmCd 1150)

150 minutes

Written examination duration (30 minutes per subject)

Q-Net 필기시험 접수안내 (기사·산업기사 과목별 30분)

40 / 60

Passing standard: 40% individual subject floor (과락) and 60% overall average

National Technical Qualifications Act Enforcement Rules

KRW 19,400

Written exam registration fee

Q-Net 전기기사 page, checked 2026-09-20

KRW 22,600

Practical exam registration fee

Q-Net 전기기사 page, checked 2026-09-20

2 years

Exemption duration for written test pass

National Technical Qualifications Act Enforcement Decree Article 21

전기기사 is South Korea's flagship Engineer-grade electrical qualification (jmCd 1150, 기후에너지환경부 / HRD Korea). The official written exam comprises 100 MCQs across five subjects (20 per subject, 30 min each, 150 min total) requiring a 40% per-subject floor (과락) and 60% overall average, followed by a 2.5-hour descriptive practical exam (필답형) in electrical facility design and management. Official Q-Net fees are KRW 19,400 (written) and KRW 22,600 (practical). OpenExamPrep provides an independent 100-question English MCQ practice bank.

Sample Engineer Electricity Practice Questions

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

1Two point charges of +2.0 μC each are placed 20 cm apart in free space (진공). What is the magnitude of the Coulomb force (쿨롱힘) between them? Use 1/(4πε0) = 9.0 × 10^9 N·m²/C².
A.1.80 N
B.9.0 N
C.0.090 N
D.0.90 N
Explanation: Coulomb's law gives F = (1/(4πε0)) q1 q2 / r². Substituting the values yields F = (9.0 × 10^9) × (2.0 × 10^-6)² / (0.20)² = (9.0 × 10^9) × (4.0 × 10^-12) / 0.040 = 0.90 N, repulsive because the charges have the same sign. This vacuum-electrostatics calculation is a standard 전기자기학 item on the 전기기사 written paper.
2An infinite straight line charge (무한직선전하) of linear density λ = 2.0 μC/m lies in free space. What is the electric field intensity at a radial distance of 10 cm from the line? Use Gauss's theorem (가우스의 정리) and ε0 = 8.854 × 10^-12 F/m.
A.3.60 × 10^4 V/m radially inward
B.7.20 × 10^5 V/m radially inward
C.1.80 × 10^5 V/m radially outward
D.3.60 × 10^5 V/m radially outward
Explanation: A cylindrical Gaussian surface of radius r and length ℓ encloses charge λℓ, so ∮ D · dA = λℓ gives D = λ / (2π r) and E = λ / (2π ε0 r) in free space. Substituting λ = 2.0 × 10^-6 C/m and r = 0.10 m yields E = 2.0 × 10^-6 / (2π × 8.854 × 10^-12 × 0.10) ≈ 3.60 × 10^5 V/m, directed radially outward for a positive line charge.
3Which integral statement is Faraday's law of electromagnetic induction (패러데이의 전자유도법칙) as used in Maxwell's equations (맥스웰 방정식)?
A.∮ B · dA = 0
B.∮ D · dA = Q_free,enc
C.∮ E · dl = − dΦ_B / dt
D.∮ H · dl = I_free,enc + dΦ_D / dt
Explanation: Faraday's law states that the circulation of E around a closed path equals the negative rate of change of magnetic flux through any surface bounded by that path: ∮ E · dl = − dΦ_B / dt. The minus sign is Lenz's law (렌츠의 법칙). The remaining Maxwell integrals are Gauss for B, Gauss for D, and the Ampere–Maxwell law.
4In a linear dielectric, the electrostatic energy density (정전 에너지밀도) stored in the electric field is which of the following?
A.σ E [surface-charge times field]
B.ε E [equal to D]
C.(1/2) μ H² [magnetic energy density]
D.(1/2) ε E² [also equal to (1/2) D · E]
Explanation: The electrostatic energy stored in a linear isotropic dielectric is W = (1/2) ∫ D · E dV, so the energy density is (1/2) D · E = (1/2) ε E². Magnetic energy density (1/2) B · H is a magnetostatic analogue and must not be mixed into an electrostatic energy question.
5A long straight wire in free space carries 10 A. Using Ampere's circuital law (암페어의 주회법칙), what is the magnetic flux density B at a radial distance of 5.0 cm from the wire? μ0 = 4π × 10^-7 H/m.
A.4.0 μT, parallel to the wire
B.80 μT, radial from the wire
C.20 μT, azimuthal around the wire
D.40 μT, azimuthal around the wire
Explanation: For an infinite straight current, ∮ H · dl = I gives H = I / (2π r) and B = μ0 I / (2π r). Substituting I = 10 A and r = 0.050 m yields B = (4π × 10^-7 × 10) / (2π × 0.050) = 4.0 × 10^-5 T = 40 μT. The direction is azimuthal, given by the right-hand rule (암페어의 오른손 법칙).
6The instantaneous Poynting vector (포인팅벡터) in an electromagnetic field is defined as which of the following, and what physical quantity does it represent?
A.S = H · B; magnetic co-energy
B.S = D × B; stored energy per unit volume
C.S = E · D; electrostatic pressure on a conductor
D.S = E × H; instantaneous power flow per unit area
Explanation: The Poynting vector S = E × H gives the instantaneous electromagnetic power flux density (W/m²). Its direction is the direction of energy transport, and the flux of S through a closed surface equals the instantaneous power leaving that volume (Poynting's theorem). Average power in a time-harmonic field uses (1/2) Re{E × H*} with peak phasors.
7A parallel-plate capacitor has plate area A = 0.020 m², plate separation d = 2.0 mm, and a dielectric of relative permittivity εr = 4.0 filling the gap. What is its capacitance? Use ε0 = 8.854 × 10^-12 F/m.
A.89 pF
B.177 pF
C.354 pF
D.708 pF
Explanation: For a parallel-plate capacitor, C = εr ε0 A / d. Substituting gives C = 4.0 × 8.854 × 10^-12 × 0.020 / 0.0020 = 3.5416 × 10^-10 F ≈ 354 pF. Filling the entire gap with εr = 4 multiplies the vacuum capacitance by four.
8Isolated concentric spherical conductors in vacuum have inner radius a = 5.0 cm and inner surface of the outer sphere b = 10 cm. What is the capacitance of this spherical capacitor? Use 1/(4πε0) = 9.0 × 10^9 m/F.
A.5.6 pF
B.56 pF
C.22 pF
D.11 pF
Explanation: The capacitance of concentric spheres is C = 4πε0 a b / (b − a). With a = 0.050 m and b = 0.10 m, a b / (b − a) = 0.10 m, so C = 0.10 / (9.0 × 10^9) = 1.11 × 10^-11 F ≈ 11 pF. This is a standard 진공 중의 도체계 capacitance on the 전기자기학 paper.
9A coaxial cylindrical capacitor (동축원통) in vacuum has inner conductor radius a and inner radius of the outer conductor b = e a, so ln(b/a) = 1. What is the capacitance per unit length? Use ε0 = 8.854 × 10^-12 F/m.
A.24.1 pF/m
B.8.85 pF/m
C.111 pF/m
D.55.6 pF/m
Explanation: Capacitance per unit length of a coaxial pair is C' = 2π ε / ln(b/a). In vacuum with ln(b/a) = 1, C' = 2π ε0 = 2π × 8.854 × 10^-12 ≈ 55.6 pF/m. The same logarithm appears in the coaxial inductance L' = (μ / 2π) ln(b/a).
10At a charge-free interface between two linear dielectrics (유전체 경계면), which pair of field-component conditions is correct?
A.Tangential H is discontinuous by free surface current and normal B is discontinuous
B.Tangential E is continuous and normal E is continuous
C.Tangential D is continuous and normal D is continuous
D.Tangential E is continuous and normal D is continuous
Explanation: From ∮ E · dl = 0 in statics, the tangential component of E is continuous across the interface. From Gauss's law for D, the normal component of D is continuous if the free surface charge ρs is zero. Normal E and tangential D are not continuous unless ε1 = ε2. Magnetic interface conditions are a separate magnetostatic statement.

About the Engineer Electricity Exam

Engineer Electricity (전기기사) is South Korea's benchmark Engineer-grade national technical qualification in electrical engineering, administered by the Human Resources Development Service of Korea (HRD Korea / Q-Net) under the Ministry of Climate, Energy and Environment (기후에너지환경부). The written examination evaluates 100 four-option multiple-choice questions across five core disciplines: Electromagnetics, Power Engineering, Electrical Machinery, Circuit Theory & Control Engineering, and Technical Standards for Electrical Facilities (Korea Electrotechnical Code - KEC). Candidates passing the written paper advance to a 2.5-hour descriptive practical examination (필답형) covering electrical facility design calculations, protective coordination, load schedules, and safety management (전기설비설계 및 관리). OpenExamPrep provides an independent English-language MCQ study adaptation designed for mastery of foundational electrical principles, mathematical calculations, and Korean technical terminology.

Exam sponsor: HRD Korea (Q-Net) / Ministry of Climate, Energy and Environment (기후에너지환경부). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

Written paper covering 전기자기학 (Electromagnetics), 전력공학 (Power Engineering), 전기기기 (Electrical Machinery), 회로이론 및 제어공학 (Circuit Theory & Control Engineering), and 전기설비기술기준 (Technical Standards for Electrical Facilities / KEC) with 20 items and 30 minutes each (100 items / 150 minutes total), followed by a 2.5-hour, 100-point written descriptive practical examination in 전기설비설계 및 관리. OpenExamPrep study weights cover all five written subjects.

Time Limit

150 minutes for the five written subjects (30 minutes each); practical: 2.5 hours written descriptive

Passing Score

Written: 40+ per subject (과락 floor) and 60 average; practical: 60/100

Exam / Certification Fees

KRW 19,400 written / KRW 22,600 practical (Q-Net, 2026-09-20)

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.

20%

Electromagnetics (전기자기학)

Coulomb's law, electric field intensity and potential, Gauss's divergence theorem, capacitors (concentric spheres, coaxial cylinders, parallel plates), energy density, dielectric boundary conditions, steady current density, Biot-Savart and Ampere's laws, magnetic vector potential and boundaries, self/mutual inductance, Faraday's law, Maxwell's equations, and Poynting vector.

20%

Power Engineering (전력공학)

Generation overview (hydro, thermal, nuclear), transmission line conductors (ACSR) and sag calculations, ABCD parameters, surge impedance, Ferranti effect, corona disruptive voltage and power loss, symmetrical components, per-unit fault analysis (3-phase, single line-to-ground), neutral grounding methods, protective relaying (differential, distance, Buchholz), and surge arresters.

20%

Electrical Machinery (전기기기)

DC machines (induced EMF, torque equation, armature reaction, interpoles, Ward-Leonard speed control), transformers (equivalent circuit, voltage regulation, core/copper losses, max efficiency Pi = Pcu, Y-Δ and V-V connections), induction motors (slip, rotor frequency, torque-slip characteristic, star-delta and inverter starting), synchronous machines (EMF equation, synchronous reactance, short-circuit ratio SCR, V-curves), and power electronics (rectifiers, converters, inverters).

20%

Circuit Theory and Control Engineering (회로이론 및 제어공학)

Network theorems (Thevenin, Norton, superposition, maximum power transfer), AC phasors and resonance (series/parallel, Q-factor), three-phase power calculations and two-wattmeter method, transient analysis of RL/RC/RLC circuits, two-port network parameters, transfer functions and signal flow graphs, second-order time-domain specifications (damping ratio, natural frequency, overshoot), Routh-Hurwitz stability criterion, root locus, and Bode/Nyquist frequency stability.

20%

Technical Standards for Electrical Facilities (전기설비기술기준 / KEC)

Korea Electrotechnical Code (KEC) provisions, voltage tier boundaries (AC low ≤ 1,000 V, DC low ≤ 1,500 V, high, extra-high > 7,000 V), dielectric withstand voltage tests (1.5x, 1.25x, 0.92x factors), earthing system topologies (TN-S, TN-C-S, TT, IT), electric shock protection (automatic disconnection times, RCD ≤ 30 mA, ≤ 0.03 s), wiring methods (metal conduit, cable tray, bus duct), overhead clearances, and renewable energy facility safety (PV, ESS, EV charging).

Preparing for the Engineer Electricity Exam

What You Need to Know

  • Passing score: Written: 40+ per subject (과락 floor) and 60 average; practical: 60/100
  • Assessment: Written paper covering 전기자기학 (Electromagnetics), 전력공학 (Power Engineering), 전기기기 (Electrical Machinery), 회로이론 및 제어공학 (Circuit Theory & Control Engineering), and 전기설비기술기준 (Technical Standards for Electrical Facilities / KEC) with 20 items and 30 minutes each (100 items / 150 minutes total), followed by a 2.5-hour, 100-point written descriptive practical examination in 전기설비설계 및 관리. OpenExamPrep study weights cover all five written subjects.
  • Time limit: 150 minutes for the five written subjects (30 minutes each); practical: 2.5 hours written descriptive
  • Exam / certification fees: KRW 19,400 written / KRW 22,600 practical (Q-Net, 2026-09-20) Official sources

Using Our Practice Resources

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

Engineer Electricity: Suggested Study Strategy

1Prioritize heavy mathematical calculation topics early: Electromagnetics (전기자기학) and Circuit Theory (회로이론) involve dense calculus and vector algebra. Learn standard shortcut formulas and coordinate system symmetries to preserve time during the 30-minute-per-subject allocation.
2Beware of the 40% subject floor (과락): Electromagnetics historically yields the highest rate of disqualification due to difficult theoretical derivations. Ensure you can reliably solve standard problems (capacitance of concentric cylinders, boundary conditions, inductances) to exceed the 8-correct threshold.
3Align with the updated Korea Electrotechnical Code (KEC): South Korea replaced legacy technical standards with KEC (effective January 2021). Familiarize yourself with modern internationalized terminology (TN-S, TN-C-S, TT, IT earthing, AC low voltage ≤ 1,000 V, DC low voltage ≤ 1,500 V) rather than obsolete Class 1/2/3/Special grounding classes.
4Prepare for the descriptive practical examination in parallel: Power engineering concepts (voltage drop, short-circuit current, transformer sizing, capacitor bank calculation for power factor improvement) and KEC installation standards reappear directly as open-ended numerical problems and single-line diagram analysis on the 2.5-hour descriptive practical paper (필답형).

Frequently Asked Questions

What is the official structure of the Engineer Electricity (전기기사) examination?

The official exam consists of two sequential phases. Phase 1 is a 150-minute written examination featuring 100 four-option multiple-choice questions (20 questions across each of five subjects: Electromagnetics, Power Engineering, Electrical Machinery, Circuit Theory & Control Engineering, and Technical Standards for Electrical Facilities / KEC). Phase 2 is a 2.5-hour descriptive written practical exam (필답형) in Electrical Facility Design and Management (전기설비설계 및 관리), worth 100 points.

What are the passing criteria and the 'gwarak' (과락) rule?

To pass the written examination, a candidate must obtain an overall average score of at least 60% (60 out of 100 questions correct across all five subjects) AND achieve at least 40% in every individual subject (at least 8 out of 20 correct per subject). Scoring below 40% (fewer than 8 correct) in any single subject results in an automatic fail ('gwarak', 과락), regardless of the total score. The practical exam requires at least 60 points out of 100.

What are the exam registration fees and where do candidates register?

As published on Q-Net (jmCd 1150, verified for 2026), the written exam registration fee is KRW 19,400, and the practical exam fee is KRW 22,600. Registration is conducted online through the official HRD Korea portal (q-net.or.kr) during designated national testing windows.

How long is a written exam pass valid for the practical exam?

Under Article 21 of the Enforcement Decree of the National Technical Qualifications Act (국가기술자격법 시행령 제21조), a candidate who passes the written examination is granted an exemption from the written test for exactly 2 years from the date of the written pass announcement, during which they can challenge the practical examination.

What is OpenExamPrep's relationship to the official Q-Net examination?

OpenExamPrep provides an independent English-language MCQ practice bank covering the written topics and Korean technical terminology. It is not affiliated with or endorsed by HRD Korea. The official Q-Net examination is administered in Korean, and candidates must take the official written and practical tests through Q-Net.