SSC JE electrical Mock Test Paper 2019| MES Electrical

Ques.81. A circuit breaker is rated as 1000A, 1000 MVA, 33 kV, 3 sec, 3-phase oil circuit breaker then calculate the value of making current in (kA) of circuit breaker

1. 44.61 kA
2. 55.32 kA
3. 32.32 kA
4. 99.99 KA

Show Explanation

Ques.82. A 500 kVA, the 3-phase transformer has iron loses of 300 W and full load copper losses of 600 W. The percentage load at which the transformer is expected to have maximum efficiency is

1. 35%
2. 50%
3. 70.7%
4. 100%

Show Explanation

Ques.83. A 3-phase delta/star transformer is supplied at 6000 V on the delta-connected side. The terminal voltage on the secondary side when supplying full load as 0.8 lagging power-factor is 415 V. The equivalent resistance and reactance drops for the transformer are 1% and 5% respectively. The turn’s ratio of the transformer is:

1. 14
2. 24
3. 42
4. 20

Show Explanation

Ques.84. A 35V source is connected to a series circuit at 600 Ω and RΩ. If a voltmeter of internal resistance is connected across the 600Ω resistor, it reads 5V. The value of R is:

1. 1.2 kΩ
2. 3.6 kΩ
3. 2.4 KΩ
4. 7.2 kΩ

Show Explanation

Ques.85. At certain current, the energy stored in iron cored coil is 1000 J and its copper loss is 2000 W. The time constant is:

1. 1
2. 1.5
3. 2
4. 2.5

Show Explanation

Ques.86. Two coils having equal resistance but different inductances are connected in series. The time constant of the series combination is the:

1. Sum of the time constant of the individual coils.
2. Average of the time constant of the individual coils.
3. The geometric mean is of the time constant of individual coils.
4. Product of the time constant of the individual coils

Show Explanation

Ques.87. The resistance of a strip of copper of rectangular cross section is 2Ω. A metal of resistivity twice that of copper is coated on its upper surface to a thickness equal to that of the copper strip. The resistance of the composite strip will be:

1. 2Ω
2. 2/3Ω
3. 4/3Ω
4. 3/4Ω

Show Explanation

Ques.88. A 50 kVA, 1000/200 V transformer takes 5 A current at a power factor of 0.2 lagging when connected to 1000 V side at no load is connected at the other side. The core loss in the transformer will be:

1. 5000 W
2. 3000 W
3. 1000 W
4. 2000 W

Show Explanation

Ques.89. In a transformer, the resistive drop is 2% and reactive drop is 5%. What will be its regulation at full load unity power factor?

1. 1%
2. 5%
3. 2%
4. 7%

Show Explanation

Ques.90. A pole, 400 V, 60 Hz, 1750 RPM, 3 phase induction motor is connected to 400 V, 50 Hz supply. The motor will:

1. Run at speed less than 1750 RPM
2. Run at speed more than 1750 RPM
3. Burn out
4. Not run at all

Show Explanation