The arc voltage produced in A.C. circuit breaker is always_____________?

A. overload
B. short-circuit and overload
C. open circuit, short-circuit and overload
D. none of the above

A. lengthening of the gap
B. cooling and blast effect
C. both (A) and (B)
D. deionizing the oil with forced air
E. none of the above

A. Radiation
B. Convection
C. Conduction
D. All of the above

A. mechanical vibration
B. insulation failure
C. loose connection
D. impulse voltage

A. generators
B. busbars
C. transformers
D. motors
E. all of the above

A. inversely proportional to the current
B. inversely proportional to the square of the current
C. proportional to the current
D. proportional to square of the current