Govt Exams Mock Test FREE | Online Quiz Competition

Q1. The condition for maximum efficiency of a D.C. generator is

Eddy current losses=stray losses.

Eddy current losses=hysteresis losses

Copper losses = 0

Variable losses = constant losses.

Q2. Statement 1: The reactive power drawn by an induction motor will be same irrespective of load torque. Statement 2: The active power drawn by an induction motor will be same irrespective of load torque. Statement 3: The reactive power drawn by an induction motor varies with the variation of load torque. Statement 4: The active power drawn by an induction motor varies with the variation of load torque. Which of these statements are true?

Statements 1 & 2

Statements 2 & 3

Statements 1 & 4

Statements 2 & 4

Q3. For a transformer, if the full load copper losses are 'A' and iron losses are 'B', then the output kVA corresponding to maximum efficiency is given by_________.

Full load × \( \sqrt{\frac{B}{A}}\)

Full load × ( \(\frac{B}{A}\) )

Full load × ( \(\frac{A}{B}\) )

Full load × \( \sqrt{\frac{A}{B}}\)

Q4. A 460 V series motor runs at 500 rpm taking a current of 40 A. Calculate the percentage change in torque if the load is changed so that the motor takes 30 A.

31.25%

56.25%

43.75%

68.75%

Q5. A 250 V DC shunt motor takes 41 A at full load. The resistance of motor armature and shunt field winding are 0.1 Ω and 250 Ω respectively. Calculate the back emf on full load.

\(E_b\)= 254 V

\(E_b\)= 250 V

\(E_b\)= 125 V

\(E_b\)= 246 V

Q6. An alternator is supplying a load of 500 kW at a p.f of 0.5 lagging. If the power factor is raised to unity, how many more kW can alternator supply for the same kVA loading?

500 kW

1000 kW

250 kW

750 kW

Q7. A 25KW,125V separately excited machine is running at constant speed of 3000 RPM with open circuit terminal voltage of 125V (consider field current as constant).The armature resistance and terminal voltage are 0.02 ohm and 128V respectively. Hence the armature current and terminal power will be

120A ,19.20KW

120A,18.75KW

150A,18.75KW

150A,19.20KW

Q8. Calculate core area of 500 kVA , 1-phase, 50 Hz, 6600/5000 V auto transformer, emf per turn = 8 V, maximum flux density 1.3 Wb/square meter

234 sq cm

337 sq cm

277 sq cm

289 sq cm

Q9. A winding of 4 pole alternator having 36 slots & a coil span of 1 to 8 is short pitched by

20 Degree

80 Degree

140 Degree

40 Degree

Q10. Determine the optimum value of load resistance for maximum power transfer if the load is connected to an amplifier of output resistance 150 Ω through a transformer with a ratio of number of turns in the primary winding to the number of turns in the secondary winding is equal to 5.

6 Ω

12 Ω

30 Ω

150 Ω

Quiz

Year 2024

August
Week # 2 Quiz 1

Q1. The condition for maximum efficiency of a D.C. generator is

Q3. For a transformer, if the full load copper losses are 'A' and iron losses are 'B', then the output kVA corresponding to maximum efficiency is given by_________.

Q4. A 460 V series motor runs at 500 rpm taking a current of 40 A. Calculate the percentage change in torque if the load is changed so that the motor takes 30 A.

Q5. A 250 V DC shunt motor takes 41 A at full load. The resistance of motor armature and shunt field winding are 0.1 Ω and 250 Ω respectively. Calculate the back emf on full load.

Q6. An alternator is supplying a load of 500 kW at a p.f of 0.5 lagging. If the power factor is raised to unity, how many more kW can alternator supply for the same kVA loading?

Q7. A 25KW,125V separately excited machine is running at constant speed of 3000 RPM with open circuit terminal voltage of 125V (consider field current as constant).The armature resistance and terminal voltage are 0.02 ohm and 128V respectively. Hence the armature current and terminal power will be

Q8. Calculate core area of 500 kVA , 1-phase, 50 Hz, 6600/5000 V auto transformer, emf per turn = 8 V, maximum flux density 1.3 Wb/square meter

Q9. A winding of 4 pole alternator having 36 slots & a coil span of 1 to 8 is short pitched by

Q10. Determine the optimum value of load resistance for maximum power transfer if the load is connected to an amplifier of output resistance 150 Ω through a transformer with a ratio of number of turns in the primary winding to the number of turns in the secondary winding is equal to 5.

Quiz

Year 2024

August Week # 4 Expire on 21 Sep 2024

September Week # 1 Expire on 30 Sep 2024

September Week # 2 Expire on 07 Oct 2024

September Week # 3 Expire on 14 Oct 2024

August Week # 2 Quiz 1

Q1. The condition for maximum efficiency of a D.C. generator is

Q3. For a transformer, if the full load copper losses are 'A' and iron losses are 'B', then the output kVA corresponding to maximum efficiency is given by_________.

Q4. A 460 V series motor runs at 500 rpm taking a current of 40 A. Calculate the percentage change in torque if the load is changed so that the motor takes 30 A.

Q5. A 250 V DC shunt motor takes 41 A at full load. The resistance of motor armature and shunt field winding are 0.1 Ω and 250 Ω respectively. Calculate the back emf on full load.

Q6. An alternator is supplying a load of 500 kW at a p.f of 0.5 lagging. If the power factor is raised to unity, how many more kW can alternator supply for the same kVA loading?

Q7. A 25KW,125V separately excited machine is running at constant speed of 3000 RPM with open circuit terminal voltage of 125V (consider field current as constant).The armature resistance and terminal voltage are 0.02 ohm and 128V respectively. Hence the armature current and terminal power will be

Q8. Calculate core area of 500 kVA , 1-phase, 50 Hz, 6600/5000 V auto transformer, emf per turn = 8 V, maximum flux density 1.3 Wb/square meter

Q9. A winding of 4 pole alternator having 36 slots & a coil span of 1 to 8 is short pitched by

Q10. Determine the optimum value of load resistance for maximum power transfer if the load is connected to an amplifier of output resistance 150 Ω through a transformer with a ratio of number of turns in the primary winding to the number of turns in the secondary winding is equal to 5.

Record & Track Your Performance

August
Week # 2 Quiz 1