Induction cup relay is operated due to changes in________________?
(A) current
(B) voltage
(C) impedance
(D) all of the above
When a wave propagates on a transmission line, it suffers reflection several times at_____________?
(A) tapping
(B) load end
(C) sending end
(D) sending and other end
(D) all of the above
The reflection co-efficient at the open circuited end of a transmission line___________?
(A) zero
(B) infinity
(C) unity
(D) none of the above
The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to______________?
(A) lubricate the contacts
(B) insulate the contacts from switch body
(C) extinguish the arc
(D) all of the above
(D) none of the above
H.R.C. fuses provide best protection against________________?
(A) overload
(B) reverse current
(C) open-circuits
(D) short-circuits
To protect most of the electrical equipment handling low power, the types of relays used are______________?
(A) thermocouple
(B) electronic and bimetallic
(C) both (A) and (B)
(D) none of the above
Which of the following is the least expensive protection for overcurrent is low voltage system ?
(A) Rewireable fuse
(B) Isolator
(C) Oil circuit breaker
(D) Air break circuit breaker
(D) None of the above
Insulation resistance of high voltage circuit breakers is more than________________?
(A) 1 mega ohms
(B) 10 mega ohms
(C) 100 mega ohms
(D) 500 mega ohms
The delay fuses are used for the protection of ___________?
(A) motors
(B) power outlet circuits
(C) fluorescent lamps
(D) light circuits
Series reactors should have________________?
(A) low resistance
(B) high resistance
(C) low impedance
(D) high impedance