Engineering
Engineering MCQs With Answers
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What is the primary role of a freewheeling diode connected across an inductive load in a converter circuit?
AIncreases supply current
BReverses direction of load current
CDissipates stored magnetic energy and prevents inductive voltage spikes
DReduces output DC voltage
In a Buck converter (step-down DC-DC chopper), the average output voltage V_o in terms of input voltage V_s and duty cycle D is:
AV_o = D * V_s
BV_o = V_s / (1 - D)
CV_o = V_s / D
DV_o = D * V_s / (1 - D)
A TRIAC can be simplified as being equivalent to:
ATwo SCRs connected in anti-parallel with a common gate
BAn SCR and a diode in series
CTwo BJTs connected back-to-back
DTwo diodes in series
A Semiconductor Controlled Rectifier (SCR) is a solid-state device containing how many PN junctions?
A4 PN junctions
B3 PN junctions
C1 PN junction
D2 PN junctions
A Mho relay (admittance relay) is inherently directional and is best suited for protecting:
ADistribution transformers
BShort transmission lines
CLong transmission lines
DMedium length transmission lines
Which distance relay is least affected by arc resistance and is preferred for short transmission lines?
AReactance relay
BImpedance relay
CMho relay
DThermal relay
Buchholz relay is a gas-actuated protective relay used exclusively for:
ASynchronous motors
BHigh-voltage alternators
CAir-cooled transformers
DOil-immersed transformers
The Merz-Price circulating current scheme for transformer protection operates on the principle of:
AOvercurrent protection
BNegative sequence detection
CDifferential protection
DDistance relaying
Which power system fault is classified as a symmetrical fault?
ASingle line-to-ground fault
BDouble line-to-ground fault
CThree-phase fault (L-L-L or L-L-L-G)
DLine-to-line fault
Bundled conductors are widely used in High Voltage (HV) and Extra High Voltage (EHV) transmission lines to:
AIncrease mechanical tension
BEliminate skin effect entirely
CReduce conductor weight
DReduce corona loss and line reactance