ELECTRICAL ENGINEERING MCQ_09

Q.146 The best location of the power factor correction equipment to be installed in the transmission line is at
A. the sending end
B. any place
C. the receiving end
D. middle of the line
Ans.: C

Q.147 The efficiency of a transformer at full load, 0.8 p.f lag is 90%. It efficiency at full load, 0.8 p.f lead will be
A. less than 90%
B. more than 90%
C. 90%
D. 80%
Ans.: C

Q.148 people can interact with each other through any part of the world through video conferencing using
A. joystick
B. speaker
C. scanner
D. webcam
Ans.: D

Q.149 A Mho relay is
A. voltage restrained directional relay
B. directional restrained over voltage relay
C. voltage controlled over current relay
D. directional restrained over current relay
Ans.: A

Q.150 Bulk power transmission over long HVDC lines are preferred on account of
A. low cost of HVDC terminals
B. Minimum line power losses
C. no harmonic problems
D. simple protection
Ans.: B

Q.151 Reactance relay is used to protect against
A. earth faults only
B. both phase and earth faults
C. phase faults only
D. over voltage faults
Ans.: A

Q.152 It is difficult to interrupt a capacitive current because
A. it has a leading power factor
B. current magnitude is very high
C. the restriking voltage can be high
D. stored energy in the capacitor is very high
Ans.: C

Q.153 The transient stability of a power system can be improved by
A. excitation control
B. single pole switching of circuit breakers
C. phase shifting transformer
D. increasing the turbine valve opening
Ans.: B

Q.154 If the dielectric strength of the medium between the contacts builds up more rapidly than the restriking voltage, the arc will
A. extinguish
B. restrike
C. increase in size
D. decrease in size
Ans.: A

Q.155 First zone distance relay protects the transmission line section up to
A. its full length
B. 25 % of its full length
C. 50% of its full length
D. 80% of its full length
Ans.: D

Q.156 A device connected to the computer which converts digital signals to analog and vice-versa is
A. modem
B. CPU
C. UPS
D. keyboard
Ans.: A

Q.157 Ybus used in power flow studies and Zbuz used in short circuit studies
A. are the same
B. are transpose of each other
C. are inverse of each other
D. have no inter relation
Ans.: D

Q.158 If a 5A fuse is blown frequently in a house lighting circuit, it is required to
A. insert a fuse of higher current rating
B. insert a fuse of higher voltage rating
C. check the load
D. reduce the load
Ans.: C

Q.159 The circuit breaker generally used in railway traction is
A. Air break C.B
B. bulk oil C.B
C. vacuum C.B
D. Minimum oil C.B
Ans.: A
Q.160 Permittivity is expressed in terms of
A. N/m
B. Weber / m
C. Farad / m
D. Farad / sq.m
Ans. C