Circuit Breaker Objective Type Questions and answers

1.  A circuit breaker normally operates

   A. When the power is to be supplied

   B. When the line is to be tested

   C. When the switch is to be put on

   D. Whenever fault occurs in the line

2.  In a circuit breaker contact wipe is necessary

   A. To decrease the speed of opening of the circuit breaker

   B. To increase the speed of opening and reduce the arcing of contacts

   C. To increase the dielectric strength across the circuit breaker contacts

   D. None of the above

3.  The fluids used in circuit breaker should be of

   A. High dielectric strength and thermal stability

   B. Non inflammability

   C. Arc extinguishing availity

   D. All of the above

4.  In circuit breakers the contact space is ionised by

   A. Field emission from the contact surface

   B. Thermal emission from the contact surface

   C. Thermal ionization of gas

   D. Any of the above

5.  For high speed circuit breaker the total clearing time is around

   A. Few minutes

   B. Few seconds

   C. 1 to 2 cycles

   D. 5 to 20 cycles

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