A
Current controlled device
B
Magnetic device
C
Power controlled device
D
Voltage controlled device
Field?Effect Transistors are voltage?controlled devices (gate voltage controls channel current).
Correct Answered :
Wrong Answered :
A
To safe guard the installation against heavy current
B
To reduce the current flowing in the circuit
C
To reduce the power consumption
D
To improve power factor
Fuses protect circuits from excessive current by blowing when current exceeds rating.
Correct Answered :
Wrong Answered :
A
X(Y+Z)=XY+YZ
B
X.(Y+Z)=X.Y+X.Z
C
X+(Y+Z) = X.Y+Z
D
X+(YZ) = X+Y+Z
Dual of distribution law X+YZ = (X+Y)(X+Z) is X(Y+Z)=XY+XZ (option B with corrected formatting).
Correct Answered :
Wrong Answered :
A
7 km
B
27.9 km
C
56.8 km
D
13.9 km
Computed I = 109.35 A and required length L ? 27.878 km to keep losses ?10% (see Excel). Choose nearest option if desired. Computed I=109.35 A, required length ? 27.878 km; nearest option B (27.9 km).
Correct Answered :
Wrong Answered :
A
100 KVA
B
141.4 KVA
C
50 KVA
D
200 KVA
Max efficiency occurs at load = rating ? sqrt(P_core/P_cu_full) =200?sqrt(1/2)=200?0.7071=141.4 KVA.
Correct Answered :
Wrong Answered :
A
Single line to ground fault
B
Double line to ground fault
C
Line to line fault
D
3 phase faults
For single line-to-ground fault, sequence currents are equal (Ia0=Ia1=Ia2).
Correct Answered :
Wrong Answered :
A
Electric field
B
Magnetic field
C
Semi permeable region
D
Insulating field
A stationary charge produces an electric field.
Correct Answered :
Wrong Answered :
A
15 W
B
20 W
C
25 W
D
50 W
Energy per cycle ? area ? scale factors =5?(2?0.05)=0.5 J per cycle; ?50 Hz =25 W.
Correct Answered :
Wrong Answered :
A
V
B
T1-T2 / T
C
V / ?2
D
T1 /T2
Since waveform magnitude is ?V, squared value is V^2 for entire period ? RMS = V.
Correct Answered :
Wrong Answered :
A
0.8
B
0.9
C
0.7
D
0.6
Using approximate regulation/tap calculations the nearest tap ratio is 0.9 (exam-type choice).
Correct Answered :
Wrong Answered :