204. Air blast circuit breakers are preferred for
A. short duty
B. intermittent duty
C. repeated duty
D. none of these

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205. The power factor of the arc in a circuit breaker is
A. zero leading
B. zero lagging
C. unity
D. any value from zero to unity

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206. For a 400 kV system, the capacity of lightning arrester should be
A. 1 kA
B. 5 kA
C. 10 kA
D. 50 kA

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207. A high speed circuit breaker can complete its operation in
A. 2 to 3 cycles
B. 3 to 8 cycles
C. 6 to 12 cycles
D. 10 to 20 cycles

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208. Which of following are the desirable qualities of protective relays?
A. speed sensitivity
B. stability,. Reliability
C. selectivity, adequacy
D. none of these

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209. Basic quantity measured in a distance relay is
A. impedance
B. voltage difference
C. current difference
D. none of these

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210. Drop out to cutoff ratio for most relays is of the order of
A. 0.2 to 0.3
B. 0.3 to 0.4
C. 0.4 to 0.6
D. 0.6 to 1.0

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