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This section includes 43 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. |
The SI unit of power is? |
A. | kW(kilo-watt) |
B. | J/s(joules per second) |
C. | Ws(watt-second) |
D. | Ws(watt-second)d) J/h(joules per hour |
Answer» C. Ws(watt-second) | |
2. |
Calculate the work done in a resistor of 20 ohm carrying 5A of current in 3 hours. |
A. | 1.5J |
B. | 15J |
C. | 1.5kWh |
D. | 15kWh |
Answer» D. 15kWh | |
3. |
Calculate the power across each 10 ohm resistance. |
A. | 1000kW, 1000kW |
B. | 1kW, 1kW |
C. | 100W, 100W |
D. | 100kW, 100kW |
Answer» C. 100W, 100W | |
4. |
Calculate the power across each 20 ohm resistance. |
A. | 1000W, 1000W |
B. | 500W, 500W |
C. | 1000kW, 1000kW |
D. | 500kW, 500kW |
Answer» C. 1000kW, 1000kW | |
5. |
A current of 5A flows in a resistor of 2 ohms. Calculate the energy dissipated in 300 seconds in the resistor. |
A. | 15kJ |
B. | 15000kJ |
C. | 1500J |
D. | 15J |
Answer» B. 15000kJ | |
6. |
Calculate the power in the 20 ohm resistance. |
A. | 2000kW |
B. | 2kW |
C. | 200kW |
D. | 2W |
Answer» C. 200kW | |
7. |
The force required to tow a vehicle at constant velocity is directly proportional to the magnitude of velocity raised to the first power. It requires 1000 W to tow with a velocity of 10 m/s. How much power is required to tow at a velocity of 8 m/s? |
A. | 320 W |
B. | 640 W |
C. | 160 W |
D. | 80 W |
Answer» C. 160 W | |
8. |
A body of mass 3 kg starts from rest with a uniform acceleration of unknown magnitude. If the body has a velocity of 30 m/s in 6 seconds, what is the power consumed in 3 seconds? |
A. | 125 W |
B. | 225 W |
C. | 325 W |
D. | 425 W |
Answer» C. 325 W | |
9. |
A 200 kg wagon climbs up a hill of slope 30-degrees in 1 minute at a speed of 36 km/h. How much power is delivered by the engine if the frictional force is 25% of the weight of the car? (Assume g = 10m/s2) |
A. | 25 kW |
B. | 50 kW |
C. | 100 kW |
D. | 125 kW |
Answer» B. 50 kW | |
10. |
A 200 kg wagon climbs up a hill of slope 30-degrees in 1 minute at a speed of 10 m/s. How much power is delivered by the engine? (Assume g = 10m/s2) |
A. | 10 kW |
B. | 20 kW |
C. | 30 kW |
D. | 40 kW |
Answer» C. 30 kW | |
11. |
1000 kW of power is supplied to a motor. 90% of this is transmitted to a machine operating at 80% efficiency. The machine lifts an object of 10-tons with a velocity _____ m/s. (Assume g = 10m/s2) |
A. | 2 |
B. | 4 |
C. | 6 |
D. | 8 |
Answer» D. 8 | |
12. |
A 2-ton vehicle travels at 20m/s on a road where the frictional force is 10% of the weight of the vehicle. What is the power required? (Assume g = 10m/s2) |
A. | 220 kW |
B. | 240 kW |
C. | 420 kW |
D. | 440 kW |
Answer» E. | |
13. |
A machine has a power of 20kW. How long will it take for it to lift a body of mass 10kg from the ground to a height of 100m? (Assume g = 10m/s2) |
A. | 1 second |
B. | 2 seconds |
C. | 3 seconds |
D. | 4 seconds |
Answer» C. 3 seconds | |
14. |
A motor is used to pump water from a depth of 5 m to fill a volume of 10 cubic meters in 5 minutes. If 50% of the power is wasted, what is the power of the motor? (Assume g = 10m/s2) |
A. | 1000/3 W |
B. | 3000/3 W |
C. | 5000/3 W |
D. | 10000/3 W |
Answer» E. | |
15. |
A motor is used to deliver water through a pipe. Let the motor have a power P initially. To double the rate of flow of water through the pipe, the power is increased to P’. What is the value of P’/P? |
A. | 2 |
B. | 4 |
C. | 6 |
D. | 8 |
Answer» E. | |
16. |
A machine gun fires 360 bullets per minute. Each bullet has a mass of 5 grams and travels at 600 m/s. What is the power of the gun? (Assume no loss of energy and 100% power transmission) |
A. | 300 W |
B. | 600 W |
C. | 900 W |
D. | 1800 W |
Answer» D. 1800 W | |
17. |
What are the units of power? |
A. | Newton |
B. | Joule |
C. | Watt |
D. | No units |
Answer» D. No units | |
18. |
Power is the time derivative of which quantity? |
A. | Energy |
B. | Acceleration |
C. | Velocity |
D. | Position |
Answer» B. Acceleration | |
19. |
Which of the following is not a unit of power? |
A. | erg/second |
B. | kgm2s-3 |
C. | Horsepower |
D. | Joule |
Answer» E. | |
20. |
The force applied on a body can be given as F = 4i + 2j + 6k. The displacement of the body is given by s = 3i + 9k. Calculate the power at t = 2 seconds. |
A. | 66 W |
B. | 33 W |
C. | 30 W |
D. | 15 W |
Answer» C. 30 W | |
21. |
What is the unit of Bond’s constant? |
A. | kW mm1/2 s/kg |
B. | kW mm s/kg |
C. | kW mm1/2 kg/s |
D. | kW mm kg/s |
Answer» B. kW mm s/kg | |
22. |
Which of the following is the correct formula of Bond’s law? |
A. | \(\frac {P}{m}\) = kb\((\frac {1}{\sqrt {D_{sb}}} + \frac {1}{\sqrt {D_{sa}}}) \) |
B. | P = kb\((\frac {1}{\sqrt {D_{sb}}} – \frac {1}{\sqrt {D_{sa}}}) \) |
C. | \(\frac {P}{m}\) = kb\((\frac {1}{\sqrt {D_{sb}}} – \frac {1}{\sqrt {D_{sa}}}) \) |
D. | P = kb\((\frac {1}{\sqrt {D_{sb}}} + \frac {1}{\sqrt {D_{sa}}}) \) |
Answer» D. P = kb\((\frac {1}{\sqrt {D_{sb}}} + \frac {1}{\sqrt {D_{sa}}}) \) | |
23. |
What are the dimensions of power? |
A. | [ML2T-3] |
B. | [ML2T-1] |
C. | [ML1T-3] |
D. | [ML3T-3] |
Answer» C. [ML1T-3] | |
24. |
What is the unit of Kick’s constant? |
A. | kg / kW |
B. | kW * s/kg |
C. | kW * kg/s |
D. | kg * s/kW |
Answer» C. kW * kg/s | |
25. |
Calculate the power required in Watts, if the work done can be given as w = 3t4 – 16t at t = 5 seconds. |
A. | 1795 W |
B. | 1420 W |
C. | 1484 W |
D. | 1675 W |
Answer» D. 1675 W | |
26. |
Work index is the gross energy required to reduce very large feed to a size such that, 65 percent of the product passes through a 100 – µm mesh screen. |
A. | True |
B. | False |
Answer» C. | |
27. |
Using Rittinger’s law, calculate the power required to crush 12 ton/hr of rocks, if 10 ton/hr rocks were crushed at a power of 9 hp. The diameter of the rocks was reduced from 3 cm to 0.5 cm in each case. |
A. | 10.7 hp |
B. | 11 hp |
C. | 10.8 hp |
D. | 12 hp |
Answer» E. | |
28. |
Automatic switching OFF function is accomplished in MCB by ______ |
A. | Relay |
B. | clutch |
C. | bimetallic-strip |
D. | diode |
Answer» D. diode | |
29. |
Full form of UPS is |
A. | Undersized Power Supply |
B. | Uninterrupted Power Supply |
C. | Uneven Power Supply |
D. | Unwanted Power Supply |
Answer» C. Uneven Power Supply | |
30. |
Phase information of UPS is of no use during |
A. | voltage dip |
B. | long sags |
C. | interruptions |
D. | All of the above |
Answer» E. | |
31. |
Consider the following statements regarding linear power supply :1. It requires a low-frequency transformer.2. It requires a high-frequency transformer.3. The transistor works in the active region.Which of the above statements is/are correct? |
A. | 1 only |
B. | 2 and 3 only |
C. | 1 and 3 only |
D. | 3 only |
Answer» D. 3 only | |
32. |
In which order the blocks appear in the block diagram of a complete regulated power supply unit? |
A. | Rectifier-regulation-filter-transformer-load |
B. | Transformer-rectifier-filter-regulator-load |
C. | Transformer-rectifier-regulator-filter-load |
D. | Rectifier-regulator-filter-transformer-load |
Answer» C. Transformer-rectifier-regulator-filter-load | |
33. |
An inverter module in a power supply converts |
A. | AC to DC |
B. | DC to AC |
C. | AC to AC |
D. | DC to DC |
Answer» C. AC to AC | |
34. |
In the SMPS regulator is accompanied by: |
A. | Duty cycle control |
B. | Regulator IC |
C. | Zener |
D. | Stabilizer |
Answer» B. Regulator IC | |
35. |
An offline UPS requires: |
A. | Inductor |
B. | Capacitor |
C. | Battery |
D. | Resistor |
Answer» D. Resistor | |
36. |
A water boiler of home is switched on to the a.c. mains supplying power at 230V/50Hz. The frequency of instantaneous power consumed by the boiler is |
A. | 0 Hz |
B. | 50 Hz |
C. | 100 Hz |
D. | 150 Hz |
Answer» D. 150 Hz | |
37. |
A solar water heater cannot be used to get hot water on a _________. |
A. | hot day |
B. | sunny day |
C. | windy day |
D. | cloudy day |
Answer» E. | |
38. |
CALCULATE_THE_WORK_DONE_IN_A_RESISTOR_OF_20_OHM_CARRYING_5A_OF_CURRENT_IN_3_HOURS.?$ |
A. | 1.5J |
B. | 15J |
C. | 1.5kWh |
D. | 15kWh |
Answer» D. 15kWh | |
39. |
The_SI_unit_of_power_is?$ |
A. | kW(kilo-watt) |
B. | J/s(joules per second) |
C. | Ws(watt-second) |
D. | J/h(joules per hour |
Answer» C. Ws(watt-second) | |
40. |
A current of 5A flows in a resistor of 2 ohms. Calculate the power in the resistor and the energy dissipated in 300 seconds. |
A. | 15kJ |
B. | 15000kJ |
C. | 1500J |
D. | 15J |
Answer» B. 15000kJ | |
41. |
Kilowatt-hour(kWh) is a unit of? |
A. | Current |
B. | Power |
C. | Energy |
D. | Resistance |
Answer» D. Resistance | |
42. |
A 250V bulb passes a current of 0.3A. Calculate the power in the lamp. |
A. | 75W |
B. | 50W |
C. | 25W |
D. | 90W |
Answer» B. 50W | |
43. |
Which of the following is not an expression power? |
A. | P=VI |
B. | P=I<sup>2</sup>R |
C. | P=V<sup>2</sup>/R |
D. | All of the mentioned |
Answer» B. P=I<sup>2</sup>R | |