A. a capackive reactance
B. an inductive reactance
C. a resistance increasing with voltage rise across the arc
D. a resistance decreasing with voltage rise across the arc
Related Mcqs:
- Which of the following medium is employed for extinction of arc in air circuit breaker?
A. Water
B. Oil
C. Air
D. SF6 - The arc voltage produced in A.C. circuit breaker is always_____________?
A. in phase with the arc current
B. lagging the arc current by 90″
C. leading the arc current by 90°
D. none of the above - Arc in a circuit breaker is interrupted at___________?
A. zero current
B. maximum current
C. minimum voltage
D. maximum voltage - The arcing contacts in a circuit breaker are made of______________?
A. copper tungsten alloy
B. porcelain
C. electrolytic copper
D. aluminium alloy - The voltage appearing across the contacts after opening of the circuit breaker is called__________voltage
A. recovery
B. surge
C. operating
D. arc
E. none of the above - Ionization in circuit breaker is facilitated by___________?
A. high temperature
B. increase of mean free path
C. increasing field strength
D. all 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 - To reduce short circuit fault currents are used_____________?
A. reactors
B. resistors
C. capacitors
D. none of the above - Air blast circuit breakers for 400 kV power system are designed to operate in_______________?
A. 100 microsecond
B. 50 millisecond
C. 0.5 sec
D. 0.1 sec - The information to the circuit breaker under fault conditions is provided by____________?
A. relay
B. rewirable fuse
C. H.R.C. only
D. all of the above
