Essential Energy Engineering Interview Questions & Answers:

1. A 68 resistor is connected across the terminals of a 3 V battery. The power dissipation of the resistor is<br>
<br>
A. 132 mW<br>
B. 13.2 mW<br>
C. 22.6 mW<br>
D. 226 mW

Option A

2. When the current through a 12 k resistor is 8 mA, the power is<br>
<br>
A. 7.68 mW<br>
B. 768 mW<br>
C. 7.68 W<br>
D. 76.8 W

Option B

3. A 75 load uses 2 W of power. The output voltage of the power supply is approximately<br>
<br>
A. 120 V<br>
B. 1.2 V<br>
C. 12 V<br>
D. 6 V

Option C

4. How much continuous current can be drawn from a 60 Ah battery for 14 h?<br>
<br>
A. 42.8 A<br>
B. 428 A<br>
C. 4.28 A<br>
D. 4.2 A

Option C

5. The power rating of a carbon-composition resistor that is to handle up to 1.2 W should be<br>
<br>
A. 2 W<br>
B. 1 W<br>
C. 5 W<br>
D. 0.5 W

Option A

6. Three hundred joules of energy are consumed in 15 s. The power is<br>
<br>
A. 2,000 W<br>
B. 2 W<br>
C. 20 W<br>
D. 200 W

Option C

7. A half-watt is equal to how many milliwatts?<br>
<br>
A. 5,000 mW<br>
B. 5 mW<br>
C. 500 mW<br>
D. 50 mW

Option C

8. A 3.3 k resistor dissipates 0.25 W. The current is<br>
<br>
A. 8.7 mA<br>
B. 87 mA<br>
C. 8.7 µA<br>
D. 8.7 A

Option A
Explanation:
W = I2R

I = square root(W/R)

= square root( 0.25/(3.3x1000) )

= 0.0087038828

= 8.7 mA

9. A 220 resistor dissipates 3 W. The voltage is<br>
<br>
A. 73.3 V<br>
B. 2.5 V<br>
C. 25.7 V<br>
D. 257 V

Option C

10. For 12 V and 40 mA, the power is<br>
<br>
A. 480 mW<br>
B. 0.480 W<br>
C. 480,000 µW<br>
D. all of the above

Option D

11. How many watt-hours represent 65 W used for 18 h?<br>
<br>
A. 11.7 Wh<br>
B. 1,170 Wh<br>
C. 11,700 Wh<br>
D. 117,000 Wh

Option B

12. If it takes 400 ms to use 12,000 J of energy, the power is<br>
<br>
A. 30 kW<br>
B. 30 W<br>
C. 3 W<br>
D. 300 kW

Option A

13. If you used 600 W of power for 60 h, you have used<br>
<br>
A. 36 kWh<br>
B. 3.6 kWh<br>
C. 10 kWh<br>
D. 1 kWh

Option A

14. In 40 kW, there are<br>
<br>
A. 0.4 mW<br>
B. 40,000 W<br>
C. 400 W<br>
D. 5,000 W

Option B

15. A 6 V battery is connected to a 300 load. Under these conditions, it is rated at 40 Ah. How long can it supply current to the load?<br>
<br>
A. 1 h<br>
B. 200 h<br>
C. 2,000 h<br>
D. 10 h

Option C

16. If you used 400 W of power for 30 h, you have used<br>
<br>
A. 1.3 kWh<br>
B. 13.3 kWh<br>
C. 1.2 kWh<br>
D. 12 kWh

Option D

17. A 120 resistor must carry a maximum current of 25 mA. Its rating should be at least<br>
<br>
A. 4.8 W<br>
B. 150 mW<br>
C. 15 mW<br>
D. 480 mW

Option B

18. At the end of a 14 day period, your utility bill shows that you have used 18 kWh. What is your average daily power?<br>
<br>
A. 1.286 kWh<br>
B. 12.85 kWh<br>
C. 535 kWh<br>
D. 252 kWh

Option A

19. A 15 V source is connected across a 12 resistor. How much energy is used in three minutes?<br>
<br>
A. 938 Wh<br>
B. 0.938 Wh<br>
C. 56.25 Wh<br>
D. 5.6 Wh

Option B

20. A given power supply is capable of providing 6 A for 3.5 h. Its ampere-hour rating is<br>
<br>
A. 0.58 Ah<br>
B. 2.1 Ah<br>
C. 21 Ah<br>
D. 58 Ah

Option C

21. A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency is<br>
<br>
A. 8.57% <br>
B. 42.85%<br>
C. 4.28% <br>
D. 85.7%

Option D

22. A certain appliance uses 350 W. If it is allowed to run continuously for 24 days, how many kilowatt-hours of energy does it consume?<br>
<br>
A. 20.16 kWh<br>
B. 201.6 kWh<br>
C. 2.01 kWh<br>
D. 8.4 kWh

Option B

23. In 0.025 W, there are<br>
<br>
A. 25 kW<br>
B. 0.00025 mW<br>
C. 2,500 µW<br>
D. 25 mW

Option D

24. When the pointer of an analog ohmmeter reads close to zero, the resistor being measured is<br>
<br>
A. overheated <br>
B. shorted<br>
C. open <br>
D. reversed

Option B

25. A 33 half-watt resistor and a 330 half-watt resistor are connected across a 12 V source. Which one(s) will overheat?<br>
<br>
A. 33 <br>
B. 330 <br>
C. both resistors<br>
D. neither resistor

Option D

26. Do you know how does energy engineering job benefit the environment?

It is a direct impact on the environment:
lower energy usage results in lower green house gases which positively impacts the environment. The benefit is very direct.

27. Do you know what energy systems engineers do?

► Manage operations of a wind turbine farm
► Analyze efficiency of hydro-electric power systems
► Oversee production of innovative fuel-cell technologies
► Evaluate the economic viability of new solar power installations
► Assess the environmental impact of alternative energy systems

28. What is Energy Engineering?

Energy engineering is a broad field of engineering dealing with energy efficiency, energy services, facility management, plant engineering, environmental compliance and alternative energy technologies. Energy engineering is one of the more recent engineering disciplines to emerge.