Electrical Engineering - Energy and Power

Exercise :: Energy and Power - General Questions

16. 

For 12 V and 40 mA, the power is

A. 480 mW
B. 0.480 W
C. 480,000 µW
D. all of the above

Answer: Option D

Explanation:

No answer description available for this question. Let us discuss.

17. 

A 220 resistor dissipates 3 W. The voltage is

A. 73.3 V
B. 2.5 V
C. 25.7 V
D. 257 V

Answer: Option C

Explanation:

No answer description available for this question. Let us discuss.

18. 

A 3.3 k resistor dissipates 0.25 W. The current is

A. 8.7 mA
B. 87 mA
C. 8.7 µA
D. 8.7 A

Answer: Option A

Explanation:

W = I2R

I = square root(W/R)

= square root( 0.25/(3.3x1000) )

= 0.0087038828

= 8.7 mA


19. 

A half-watt is equal to how many milliwatts?

A. 5,000 mW
B. 5 mW
C. 500 mW
D. 50 mW

Answer: Option C

Explanation:

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20. 

Three hundred joules of energy are consumed in 15 s. The power is

A. 2,000 W
B. 2 W
C. 20 W
D. 200 W

Answer: Option C

Explanation:

No answer description available for this question. Let us discuss.