11) The power efficiency of a lighting transformer is always……..its all-day efficiency.
a) equal to
b) higher than
c) less than
d) none of the above
12) What is the approximate efficiency of large transformers?
a) 65%
b) 75%
c) 85%
d) 95%
13) The inductive reactance of a transformer depends on
a) e.m.f.
b) m.m.f.
c) leakage flux
d) magnetic flux
14) How are transformers generally cooled for installations rated at less than 5 kVA?
a) oil cooled
b) air cooled
c) water cooled
d) none of the above
15) The transformer that does not provide electric isolation is
a) power transformer
b) autotransformer
c) current transformer
d) potential transformer
Best Wishes for the All Candidates!!
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