Electrical Engineering

Electrical Engineering – Verified PYQ Authority Guide

Electrical Engineering is 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

18 verified PYQs are currently mapped to this Sub Subject hub. The represented years include 2024. Exam coverage currently includes BMS. Subject context includes Electrical 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. Consider the circuit shown in Fig. Q46. The switch is initially closed for a long time and opens at t = 0s. What is the value of R1 and R2, if current…
   BMS · 2024 · Finding R1 and R2 from Current Response
   For an RL switching response i(t)=I∞+(I0+−I∞)e⁻ᵗ/τ, the given expression identifies I∞=2.5 A, the initial current as 4 A, and τ=1/4 s. Applying the pre-switch…
2. Consider the following circuit shown in Fig. Q38 and read the following statements. Statement 1: The current through the capacitor can be obtained by using only source transformation without the use of…
   BMS · 2024 · Different-Frequency Sources
   The network is linear, so superposition can be used by analyzing the response to each sinusoidal source at its own frequency and then adding…
3. A battery has a short-circuit current of 30 A and an open-circuit voltage of 12 V. If the battery is connected to a load resistance of 2Ω, then what will be the…
   BMS · 2024 · Power Delivered to Load
   The battery internal resistance is found from open-circuit voltage and short-circuit current: r=12/30=0.4 Ω. With a 2 Ω load the current is 12/(2+0.4)=5 A,…
4. The ideal transformer in Fig. Q49 has N2/N1 = 10. What will be the ratio V2/V1? Fig. Q49
   BMS · 2024 · Turns Ratio and Polarity
   For an ideal transformer, voltage magnitude follows the turns ratio, |V2/V1|=N2/N1=10. The dot/polarity marking in the figure makes the referenced secondary voltage opposite in…
5. For the circuit shown in Fig. Q48, what will be the capacitor voltage at t = 0–s (just before the switch is closed). Fig. Q48
   BMS · 2024 · Capacitor Voltage at 0−
   Before switching, the circuit has been in its stated pre-switch condition long enough for the capacitor voltage to be determined by that network. The…
6. A parallel RLC circuit has L = 2 H and C = 250 mF. What should be the value of R such that the damping factor of the circuit becomes unity?
   BMS · 2024 · Damping Factor of Parallel RLC
   For a parallel RLC circuit the damping factor is α=1/(2RC). With C=0.25 F and the required damping factor α=1 s⁻¹, R=1/(2×0.25×1)=2 Ω.
7. Calculate the power absorbed by 4 kΩ resistor for the circuit shown in Fig. Q45. Fig. Q45
   BMS · 2024 · Power in a 4 kΩ Resistor
   Using the circuit solution, the voltage/current across the 4 kΩ branch gives a resistor power of 4 mW. Power can be checked with P=V²/R…
8. In the context of Gujarat Small Hydel policy 2016, which of the following correctly shows the station capacity defined for Micro Hydel projects?
   BMS · 2024 · Micro Hydel Capacity
   Under the Gujarat Small Hydel Policy 2016 classification used by the question, a Micro Hydel project corresponds to a station capacity of 100 kW.…

Formula & key-relationship bank from verified solutions

• i(t)=I∞+(I0+−I∞)e⁻ᵗ/τ; τ=0.25 s; R1=3Ω, R2=5Ω
• iC(t)=iC,ω=2(t)+iC,ω=10(t)
• r=Voc/Isc=0.4Ω; I=12/2.4=5A; PL=I²RL=50W
• V2/V1=−N2/N1=−10
• vC(0+)=vC(0−)=0 V
• α=1/(2RC); R=1/(2Cα)=2Ω

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

• For an RL switching response i(t)=I∞+(I0+−I∞)e⁻ᵗ/τ, the given expression identifies I∞=2.5 A, the initial current as 4 A, and τ=1/4 s. Applying the pre-switch and post-switch DC equivalents and τ=L/Req gives R1=3 Ω and R2=5 Ω.
• The network is linear, so superposition can be used by analyzing the response to each sinusoidal source at its own frequency and then adding the time-domain currents. Because the two sources operate at different frequencies and the reactive…
• The battery internal resistance is found from open-circuit voltage and short-circuit current: r=12/30=0.4 Ω. With a 2 Ω load the current is 12/(2+0.4)=5 A, so load power is I²R=25×2=50 W.
• For an ideal transformer, voltage magnitude follows the turns ratio, |V2/V1|=N2/N1=10. The dot/polarity marking in the figure makes the referenced secondary voltage opposite in polarity to the referenced primary voltage, so V2/V1=−10.
• Before switching, the circuit has been in its stated pre-switch condition long enough for the capacitor voltage to be determined by that network. The shown connection leaves the capacitor uncharged before the switch closes, so vC(0−)=0 V. Capacitor…

Exam tips already validated in SRO solutions

• Read I∞, I0+ and τ directly from the exponential form first.
• Different frequencies → solve separately, then superpose in time.
• Short-circuit current reveals the internal resistance.
• Turns ratio gives magnitude; dot convention determines the sign.
• Determine the pre-switch steady state first, then use capacitor-voltage continuity.

Common mistakes to avoid

• Do not assume the coefficient of e⁻⁴ᵗ is the final current.
• Do not add phasors belonging to different frequencies.
• Do not use 12 V directly across the load when the battery has internal resistance.
• Do not ignore the indicated voltage reference directions and dot polarity.
• Do not calculate vC(0−) from the post-switch circuit.

Topic and concept coverage

Mapped topic labels include AC Circuits, DC Circuits, Electric Circuits, Network Theory, Transient Circuits, AC Power, Analog Filters. The concept trail includes Capacitor Voltage at 0−, Complex Conjugate Load Matching, Damping Factor of Parallel RLC, Different-Frequency Sources, Finding R1 and R2 from Current Response, Low-Pass Roll-Off, Micro Hydel Capacity, Neutral Current in Balanced System. 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 with Electrical Engineering, AC Circuits, AC Circuits, AC Circuits, AC Circuits, AC Circuits, Electric Circuits, Transient Circuits, Capacitor Voltage at 0−, Complex Conjugate Load Matching, Damping Factor of Parallel RLC. 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.