MCQ – Basic Electrical
1. Open
circuit test in a transformer is performed with
§ rated transformer voltage
§ rated transformer current
§ direct current
§ high frequency supply
2. In
performing the short circuit test on a transformer
§ high voltage side is usually
short circuited
§ low voltage side is
usually short circuited
§ any side is usually short
circuited
§ none of the above
3. In a
transformer
§ both open and short
circuit tests are performed on LV side
§ Open circuit test is
conducted in HV side and short circuit test on LV side
§ Open circuit test is
performed on LV side and short circuit test on HV side
§ both Open and short
circuit tests are performed on HV side
4.
Power factor of a ac circuit is defined as
§ PF=cosθ
§ PF=R/|z|
§ PF=P(real)/P(app)
§ all of the above
5.
Power factor PF is
§ PF α 1/I
§ PF α I
§ PF α I^2
§ PF α 1/I^2
6. A
transmission as well as distribution system of electric power is known as good
if
§ High value of voltage
regulation and efficiency
§ low value of voltage
regulation and high value of efficiency
§ Good power factor and
lower voltage regulation
§ none of the above
7.
Charcoal, common salt are used in earthing due to following reasons:
§ They increases the
conductivity of the soil
§ They increases the
contact area of the earth
§ They maintains moisture
and increase earth resistance
§ none of the above
8.
Voltage source has
§ smaller resistance than
load R
§ Higher internal
resistance than load R
§ Internal resistance is
not present i.e zero in all cases
§ very small internal
resistance
9.
Material subjected to rapid reversal of magnetism should have
§ high permeability and low
hysteresis loss
§ Large B-H loop area
§ large coercivity and high
retentivity
§ low permeability and
large coercivity
10.
Area of hysteresis loop represents
§ copper loss
§ eddy current loss
§ hysteresis loop
11.
Silicon content in steel reduces
§ hysteresis loop
§ eddy current loss
§ copper loss
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