MCQ
781. In sheet metal blanking, shear is provided on punches and dies so that--
press load is reduced
good cut edge in obtained
warping of sheet is minimized
cut blanks are straight
782. In aluminium conductors, steel core is provided to-
compensate for skin effect
neutralise proximity effect
reduce line inductance
increases the tensile strength
783. Average resistance of human body is-
500 ohms
1000 ohms
1500 ohms
2000 ohms
784. Admittance relay-
Non-directional relay
Directional relay
Differential relay
None of the above
785. Where severe synchronising swing occur, the relay employed is
Impedance relay
Mho relay
Reactance relay
Induction relay
786. In SF6 circuit breakers, the SF, gas-
has insulating properties
is non-inflammable
is non-poisonous
all of the above
787. The most severe fault on the power system is-
there phase short circuit
line to line fault
double line to ground fault
single line to ground fault
788. A thermal protection switch can protect against-
Short-circuit
Overload
Temperature
Over voltage
789. For ground fault we prefer-
Plain impedance relay
Directional over current relay
Mho relay
Reactance relay
790. The operating speed of a relay depends upon the-
Rate of flux built up
Armature core air gap
Spring tension
All of these
791. For the protection of lines against faults Involving variable fault resistance, the preferred relaying scheme is a-
Plain impedance relay
Directional over-current relay
Mho relay
Reactance relay
792. An ideal location for the substation would be at ---the of load.
Centre of gravity
Load centre
Nearer to consumer
None of the above
793. A fuse is a--
protective device
current limiting device
current controling device
none of the above
794. Factors on which soil resistance depends/RPCI--
depth of the electrode
moisture
Nacl
all the above
795. A circuit breaker is essentially-
an automatic switch
a manual switch
a high-lightning arrester
none of the above
796. Inverse time current relays are used for the protection of-
Feeders
Transformers
Alternators
Both A and B
797. Outdoor sub-station requires-space.
Less
More
Medium
Any of the above
798. IDMT relays are used to protect the power transformers against-
External short-circuit
Overloads
Internal short-circuits
Both (a) and (b)
799. The relay used for feeder protection --
Under voltage relay
Translay relay
Thermal relay
Buchholz relay
800. The main function of a fuse is to-
Protect the line
Open the circuit
Prevent excessive currents
None of the above