⚡Electrical Engineering MCQs
Electrical Engineering MCQs
499 MCQs131
A trivalent impurity has______________valence electrons?
A4
B5
C6
D3
132
Which of the following happens when star-delta starter is used ?
Aand
BD. None of the above
CBoth
133
Which of the following types of motor enclosure is safest ?
ATotally enclosed
BTotally enclosed fan cooled
COpen type
DSemi closed
134
The diameter of the rotor shaft for an electric motor depends on which of the following ?
Ar.p.m. only
BHorse power only
CHorse power and r.p.m.
DHorse power, r.p.m. and power factor
135
In series motor which of the following methods can be used for changing the flux per pole ?
ATapped field control
BDiverter field control
CSeries-parallel control
DAny of the above
136
For which of the following applications motor has to start with high acceleration ?
AOil expeller
BFloor mill
CLifts and hoists
DCentrifugal pump
137
The battery connections required to forward bias a pn junction are_________________?
A+ve terminal to p and –ve terminal to n
B-ve terminal to p and +ve terminal to n
C-ve terminal to p and –ve terminal to n
DNone of the above
138
In the depletion region of a pn junction, there is a shortage of_________________?
AAcceptor ions
BHoles and electrons
CDonor ions
DNone of the above
139
A pn junction acts as a__________________?
AControlled switch
BBidirectional switch
CUnidirectional switch
DNone of the above
140
In an intrinsic semiconductor, the number of free electrons_____________?
AEquals the number of holes
BIs greater than the number of holes
CIs less than the number of holes
DNone of the above