Basic Electrical Engineering

Basic Electrical Engineering – Verified PYQ Authority Guide

Basic Electrical Engineeringis a sub-subject authority hub. It is designed to expose the important topic/concept clusters represented by verified SRO PYQs and guide students from broad revision into the exact solved questions that support each area. Every factual learning cue below is drawn from the existing verified, published and approved English PYQ corpus or from its Knowledge Graph relationships; the hub does not invent unsupported technical claims.

PYQ evidence snapshot

16 verified PYQsare currently mapped to this Sub Subject hub. The represented years include2026, 2025. Exam coverage currently includesDeputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2,, Assistant Engineer (Electrical), Class-2, Road and Building Department. Subject context includesElectrical Engineering. These values come from live mappings and can expand automatically when new verified PYQs are added.

Most useful verified PYQs to solve first

Start with the actual questions rather than memorising a generic note. The links below are ranked from the mapped corpus using repeat history and editorial quality, while the complete explanation stays on the individual question page.

1. A parallel circuit consists of two branches: one with impedance (4 + j3) Ω and another with (4 − j3) Ω connected to 100 V supply. Then 1. The total impedance is…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Conjugate Impedances in Parallel
   The equivalent resistance is not simply R; it is obtained after adding the two admittances. Complex-conjugate multiplication gives |4+j3|²=25. Adding admittances cancels ±j3/25 exactly.…
2. A load consumes 1000 W at 0.8 lagging power factor. Then 1. Apparent power is 1250 VA. 2. Reactive power is 750 VAR. 3. Current increases if power factor decreases. 4. Power…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Real Reactive and Apparent Power
   Its magnitude |S| is apparent power in VA, while P is measured in W and Q in var. S=P/PF=1000/0.8=1250 VA. Q=√(S²−P²)=750 var. Key relation:…
3. An AC voltage is given by v(t) = 100 sin(ωt). Then 1. Peak voltage is 100 V. 2. RMS voltage is 100/√2. 3. RMS value ≈ 70.7 V. 4. Average value over…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Peak RMS and Average Values
   The average of a rectified sine over a half cycle is 2Xm/π, giving sine-wave form factor RMS/average-rectified ≈1.11. For v(t)=100 sinωt, Vm=100 V and…
4. Two resistors of 6 Ω and 3 Ω are connected in parallel across 12 V supply. Then 1. Equivalent resistance is 2 Ω. 2. Total current is 6 A. 3. Current through…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Parallel Resistor Current and Power
   Equivalent resistance is found from reciprocal addition, total current is the sum of branch currents, and total real power is the sum of branch…
5. A DC circuit consists of a resistor of 10 Ω connected across a 20 V supply. With reference to current and power, consider the following statements: 1. The current flowing through the…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Resistive DC Circuit Calculations
   At fixed supply voltage, doubling resistance halves current and halves power because P=V²/R. Given V=20 V and R=10 Ω: I=V/R=2 A and P=VI=40 W.…
6. Consider the following statements regarding three-phase systems: 1. Total power = √3 VL IL cosϕ. 2. Power is constant in balanced system. 3. Neutral current is zero in balanced load. Which of…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Three-Phase Power and Neutral Current
   A balanced three-phase system has three equal-magnitude phase quantities displaced by 120°. For a balanced load, the instantaneous total three-phase power is constant and…
7. Consider the following statements: 1. RMS value of sinusoidal current is its peak value divided by √2. 2. Average value of sinusoidal current over one cycle is zero. 3. Form factor of…
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · RMS Average and Form Factor
   For a sine wave x(t)=Xm sinωt, the RMS value is Xm/√2. The average of a rectified sine over a half cycle is 2Xm/π, giving…
8. Consider the following statements regarding power factor correction: 1. It reduces line current. 2. It reduces copper losses. 3. It improves voltage regulation. Which of the above statements is/are correct?
   Deputy Executive Engineer (Electrical), Class-2, Sports Authority of Gujarat / Assistant Engineer (Electrical), Class-2, · 2026 · Benefits of Power Factor Correction
   For a fixed real-power load and supply voltage, poor power factor requires higher current. Raising power factor with shunt capacitors or an over-excited synchronous…

Formula & key-relationship bank from verified solutions

• Yeq = 1/(4+j3)+1/(4−j3)=8/25=0.32 S; Zeq=1/Yeq=3.125 Ω; I=V/Zeq=32 A; PF=cos0°=1.
• S=P+jQ; |S|=√(P²+Q²); PF=P/|S|=cosφ.
• Xrms=Xm/√2; Xavg(rectified)=2Xm/π; form factor≈1.11.
• 1/R_eq=Σ(1/R_i); I_i=V/R_i; P_total=V I_total.
• I=V/R; P=VI=I²R=V²/R.
• P=√3 V_L I_L cosφ.

Use these as revision triggers and open the linked PYQ before applying a formula numerically; variable definitions and assumptions belong to the exact solved question.

Core ideas repeatedly reinforced by the solved corpus

• The equivalent resistance is not simply R; it is obtained after adding the two admittances. Complex-conjugate multiplication gives |4+j3|²=25. Adding admittances cancels ±j3/25 exactly. Key relation: Yeq = 1/(4+j3)+1/(4−j3)=8/25=0.32 S; Zeq=1/Yeq=3.125 Ω; I=V/Zeq=32 A; PF=cos0°=1. Exam focus: For…
• Its magnitude |S| is apparent power in VA, while P is measured in W and Q in var. S=P/PF=1000/0.8=1250 VA. Q=√(S²−P²)=750 var. Key relation: S=P+jQ; |S|=√(P²+Q²); PF=P/|S|=cosφ. Exam focus: Draw the power triangle before choosing a power-factor relation.…
• The average of a rectified sine over a half cycle is 2Xm/π, giving sine-wave form factor RMS/average-rectified ≈1.11. For v(t)=100 sinωt, Vm=100 V and Vrms=Vm/√2≈70.7 V. The full-cycle average of a sine wave is zero. Key relation: Xrms=Xm/√2;…
• Equivalent resistance is found from reciprocal addition, total current is the sum of branch currents, and total real power is the sum of branch powers. For 6 Ω || 3 Ω, Req=(6×3)/(6+3)=2 Ω. Total current=12/2=6 A. Key relation:…
• At fixed supply voltage, doubling resistance halves current and halves power because P=V²/R. Given V=20 V and R=10 Ω: I=V/R=2 A and P=VI=40 W. If R doubles to 20 Ω at the same 20 V, I=1 A and…

Exam tips already validated in SRO solutions

• For parallel complex branches, convert Z to Y first; it prevents sign and denominator mistakes.
• Draw the power triangle before choosing a power-factor relation.
• Check whether the question asks full-cycle average or rectified average.
• Solve branch currents first when the same supply voltage appears across every resistor.
• At fixed V, power varies inversely with R.

Common mistakes to avoid

• Directly adding parallel impedances or assuming the equivalent resistance equals the real part of each branch.
• Do not confuse P/Q with power factor.
• Using the half-cycle average as the full-cycle average is a common error.
• Adding parallel resistances directly is incorrect.
• Do not assume power stays constant when resistance changes on a fixed-voltage source.

Topic and concept coverage

Mapped topic labels includeAC Fundamentals, AC Circuits, DC Circuits, Power Factor, Three-Phase Circuits, Current and Current Density, Electric Charge. The concept trail includesBenefits of Power Factor Correction, Complex Power and Power Factor, Conjugate Impedances in Parallel, Current Density, Cycles from Frequency, Heating-Effect Definition of RMS, Line and Phase Voltage in Delta, Number of Electrons. Use these labels as a revision map: move from the broad area to the narrow concept, solve a verified PYQ, inspect the detailed reasoning, and then attempt another question from the same cluster.

Knowledge Graph navigation

Continue withElectrical Engineering,AC Circuits,AC Fundamentals,Current and Current Density,DC Circuits,Electric Charge,Power Factor,Three-Phase Circuits. These are canonical SRO entity links based on the Knowledge Graph and shared question mappings, not keyword-stuffed tag pages.

How to revise this authority page efficiently

1. Solve before reading:answer a mapped PYQ first.
2. Read the exact explanation:verify the correct principle, formula, distractor logic and common mistake on that question page.
3. Move one level in the graph:use the closest concept/sub-topic/topic link rather than opening unrelated content.
4. Reattempt:solve another verified PYQ from this hub and check whether the same error repeats.

Quality scope:this page is automatically maintained from SRO’s verified mapped corpus. It enriches one canonical authority URL instead of generating multiple near-duplicate pages for keyword variants. Manual authority articles are never overwritten by the automated engine.