Energy and Power - General Questions

Directions to Solve

Energy and Power - General Questions

1.

A 68 resistor is connected across the terminals of a 3 V battery. The power dissipation of the resistor is

A.	132 mW
B.	13.2 mW
C.	22.6 mW
D.	226 mW

Answer: Option A

Explanation:

No answer description available for this question.

2.

When the current through a 12 k resistor is 8 mA, the power is

A.	7.68 mW
B.	768 mW
C.	7.68 W
D.	76.8 W

Answer: Option B

Explanation:

No answer description available for this question.

3.

A 75 load uses 2 W of power. The output voltage of the power supply is approximately

A.	120 V
B.	1.2 V
C.	12 V
D.	6 V

Answer: Option C

Explanation:

No answer description available for this question.

4.

How much continuous current can be drawn from a 60 Ah battery for 14 h?

A.	42.8 A
B.	428 A
C.	4.28 A
D.	4.2 A

Answer: Option C

Explanation:

No answer description available for this question.

5.

The power rating of a carbon-composition resistor that is to handle up to 1.2 W should be

A.	2 W
B.	1 W
C.	5 W
D.	0.5 W

Answer: Option A

Explanation:

No answer description available for this question.

6.

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.

7.

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:

No answer description available for this question.

8.

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

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