Relay | Protective Relay Objective Type Questions and answers

21.  The relay operating speed depends upon

   A. The spring tension

   B. The rate of flux built up

   C. Armature core air gap

   D. All of the above

22.  In order that current should flow without causing excessive heating or voltage drop, the relay contacts should

   A. Have low contact resistance

   B. Be clean and smooth

   C. Be of sufficient size and proper shape

   D. Have all above properties

23.  Interruption of large currents by relay requires

   A. Arc suppressing blow out coils

   B. Wide separation of the open contacts

   C. High speed opening of contacts

   D. All of the above

24.  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

25.  ............. Relays are used for phase faults on long line

   A. Impedance

   B. Reactance

   C. Either of the above

   D. None of the above

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