127. String efficiency is defined as where VE-1 is the flash over voltage of one unit VFn is the flash over voltage of string of n-units.
A. VFWVF1
B. nVFINFn
C. VF/(n VF1)
D. VFINFn

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128. The string efficiency of an insulator can be increased by
A. reducing the number of strings in the insulator
B. increasing the number of strings in the insulator
C. correct grading of insulators of various capacities
D. none of these

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129. The top most wire in a distribution line is
A. neutral wire
B. earth wire
C. phase wire
D. any of these

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130. In a 5 insulator disc string, m = 1/6. The string efficiency will be
A.29%
B.58%
C.72%
D.85%

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131. Sheaths are used in power cables to
A. provide adequate insulation
B. increase the strength of the cable
C. prevent moisture from entering the cable
D. none of these

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132. For high voltage applications, the insulators used are of
A. suspension type
B. pin type
C. strain type
D. none of these

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133. On a transmission line, whenever the conductors are dead ended or there is change in the direction of transmission line, the insulators used are
A. strain type
B. suspension type
C. pin type
D. none of these

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