MCQOPTIONS
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MCQOPTIONS
This section includes 16 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
An energy meter is designed to have 100 revolutions of the disc per unit of energy consumed. The energy consumed by the load-carrying 50 A at 230 V and 0.8 power factor. Find the percentage error if the meter actually makes 950 revolutions. |
| A. | 3.26% , Slow |
| B. | 3.15%, Slow |
| C. | 3.26% , Fast |
| D. | 3.15%, Fast |
| Answer» D. 3.15%, Fast | |
| 2. |
Boards on which various control accessories like energy meter, iron-clad switch, fuses, etc. are housed are called ______ boards. |
| A. | Panel |
| B. | Control |
| C. | Standard |
| D. | Switch |
| Answer» B. Control | |
| 3. |
Direction: It consists of two statements, one labeled as ‘Statement (I)’ and the others as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below: Statement (I): A Watt-hour meter must be calibrated at both full-rated load as well as at 10% of rated load.Statement (II): The source of error at full load is inaccurate damping and at light loads, the torque is not exactly proportional to load. |
| A. | Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) |
| B. | Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) |
| C. | Statement (I) is true but Statement (II) is false |
| D. | Statement (I) is false but Statement (II) is true |
| Answer» B. Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) | |
| 4. |
Creep error may occur induction type energy meter due to |
| A. | incorrect position of brake magnet |
| B. | incorrect adjustment of position of shading band |
| C. | overvoltage across voltage coil |
| D. | increase in temperature |
| Answer» D. increase in temperature | |
| 5. |
If an energy meter disc makes 10 revolutions in 100 sec when a load of 450 W is connected to it, the meter constant (in rev / kW-h) will be: |
| A. | 100 |
| B. | 800 |
| C. | 160 |
| D. | 500 |
| Answer» C. 160 | |
| 6. |
A domestic load consists of 10 lamps of 100 W each, three fans of 60 W each and two heaters of 1 kW each, all the loads operating for 1 hour. Energy consumed is measured using an energy-meter having a constant of 1500 revolutions per kWh. The number of revolutions recorded by the meter is 4500. The percentage error in the energy-meter reading is: |
| A. | – 5.66% |
| B. | 5.55% |
| C. | 15.66% |
| D. | -15.66% |
| Answer» B. 5.55% | |
| 7. |
Creeping in energy meter can be avoided by: |
| A. | Drilling two diametrically opposite holes in the disc. |
| B. | Using adjustable resistance. |
| C. | Providing a small shading loop between the central pole of shunt magnet and the disc. |
| D. | Using shading bands around the central limb of shunt magnet. |
| Answer» B. Using adjustable resistance. | |
| 8. |
A single phase energy meter is operating on 230 V, 50 Hz supply with a load of 20 A for two hours at UPF. The meter makes 1380 revolutions in that period. The meter constant is |
| A. | 695 rev/kWh |
| B. | 150 rev/kWh |
| C. | 0.15 rev/kWh |
| D. | 1/150 rev/kWh |
| Answer» C. 0.15 rev/kWh | |
| 9. |
A 230 V, 1-phase watt hour meter records a constant load of 10 A for 10 hours at unity p.f. If the meter disc makes 2300 revolutions during this period, what is the meter constant in revolutions/kWh? |
| A. | 300 rev/kWh |
| B. | 200 rev/kWh |
| C. | 100 rev/kWh |
| D. | 400 rev/kWh |
| Answer» D. 400 rev/kWh | |
| 10. |
In an induction-type instrument, two fluxes having a phase difference θ from a single phase supply can be achieved by: |
| A. | increasing supply voltage |
| B. | increasing frequency |
| C. | splitting phase arrangement |
| D. | changing poles |
| Answer» D. changing poles | |
| 11. |
A 230-V, single-phase domestic energy meter has a constant load of 4 A passing through it for 6 h at unity power factor. The meter disc makes 2208 revolutions during this period. What will be the energy consumed by the load if the meter disc completes 1240 revolutions? |
| A. | 2.5 kWh |
| B. | 2.8 kWh |
| C. | 3.5 kWh |
| D. | 3.1 kWh |
| Answer» E. | |
| 12. |
If an energy meter makes 5 revolutions in 100 seconds, when a load of 225 W is connected, the meter constant is |
| A. | 800 rev/kWh |
| B. | 222 rev/kWh |
| C. | 147 rev/kWh |
| D. | 13 rev/kWh |
| Answer» B. 222 rev/kWh | |
| 13. |
In an Energy Meter, what happens when magnetic field interacts with eddy current? |
| A. | A braking torque is produced which exerts force and causes the load current flow through the current coil to stop the rotating disc |
| B. | A torque is produced which exerts force and causes the disc to stop rotating |
| C. | A braking torque is produced which exerts force and causes the voltage coil to lag by 90o |
| D. | A torque is produced which exerts force and causes the disc to rotate |
| Answer» E. | |
| 14. |
In an Energy Meter the Driving System, ______________, Registering System and _____________ form the basic construction parts. |
| A. | Moving System, Parallel System |
| B. | Series System, Braking System |
| C. | Moving System, Braking System |
| D. | Magnetic Flux System, Shunt System |
| Answer» D. Magnetic Flux System, Shunt System | |
| 15. |
Consider the following statements:Adjustment is required in an induction type energy meter in the following manner so that it can be compensated for the slow down of speed on the specified load due to some unspecified reason:1) Adjusting the position of the braking magnet and moving it away from the center of the disc.2) Adjusting the position of the braking magnet and moving it closer to the center of the disc.3) Adjusting the load.Which of these statements are correct? |
| A. | 1,2 and 3 |
| B. | 1 only |
| C. | 2 only |
| D. | 3 only |
| Answer» D. 3 only | |
| 16. |
In an Energy meter, how is the shunt electromagnet connected in driving System? |
| A. | The shunt electromagnet's coil is connected with the supply and carries current inversely proportional to the resistance. |
| B. | The shunt electromagnet's coil is connected with the series magnet and carries current proportional to the resistance |
| C. | The shunt electromagnet's coil is connected with the supply and carries current proportional to the supply voltage |
| D. | The shunt electromagnet's coil is connected with the series magnet and carries current inversely proportional to the supply voltage |
| Answer» D. The shunt electromagnet's coil is connected with the series magnet and carries current inversely proportional to the supply voltage | |