48. What is the difference between common-mode and differential-mode input signals?

**A.** phase relationship
**B.** voltage

**C.** current

**D.** apparent power

**Answer: Option A **

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49. A circuit that uses an amplifier with passive filter elements is called a(n):

**A.** relaxation oscillator
**B.** signal generator
**C.** differential amplifier
**D.** active filter

**Answer: Option D **

.

50. The input offset current equals the
**A.** average of two base currents

**B.** collector current divided by the current gain
**C.** difference between two base-emitter voltages

**D.** difference between two base currents

**Answer: Option D **

**X - QUANTITIES AND UNITS **

1. Derived units are obtained from various combinations of
**A.** electrical quantities

**B.** fundamental units
**C.** metric prefixes
**D.** international standards

**Answer: Option B **

.

2. Which of the following metric prefixes could replace 10^{–9}?

**A.** Nano **B.** Mega

**C.** Kilo **D.** Micro

**Answer: Option A **

.

3. Scientific notation is a method

**A.** of expressing a very large number
**B.** of expressing a very small number

**C.** used to make calculations with large and small numbers
**D.** All of the above

**Answer: Option D **

.

4. If you drop a 5 when rounding a number, you are using the
**A.** round-to-even rule

**B.** significant digit rule
**C.** round-off rule
**D.** retained digit rule

**Answer: Option A **

.

5. 7200 mV is the same as
**A.** 7.2 V

**B.** 7.2 V
**C.** 7,200,000 V
**D.** 0.0072 V

**Answer: Option B **

6. A measure of the repeatability of a measurement of some quantity is

**A.** error **B.** precision

**C.** accuracy **D.** significant

**Answer: Option B **

.

7. Another name for "fundamental units" is
**A.** base units

**B.** atoms

**C.** the metric system
**D.** letter symbols

**Answer: Option A **

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8. Adding 27.5 × 10^{3} to 8.9 × 10^{4} equals

**A.** 36.4 × 10^{7}
**B.** 116.5 × 10^{4}
**C.** 28.39 × 10^{3}
**D.** 1.165 × 10^{5}

**Answer: Option D **

.

9. When using the terms "accuracy" and "precision" for measurements
**A.** "precision" implies less measurement error than "accuracy"

**B.** "accuracy" implies less measurement error than "precision"

**C.** "precision" measures the repeatability of a measurement
**D.** both terms mean the same thing

**Answer: Option C **

.

10. The difference between scientific and engineering notation is
**A.** powers of ten representation

**B.** single vs. multiple digits before decimal point
**C.** groupings of multiples of three digits

**D.** All of the above

**Answer: Option D **

11. The number 14.8 can also be expressed as
**A.** 1.48 × 10^{–1}

**B.** 1.48 × 10^{0}
**C.** 1.48 × 10^{1}
**D.** 1.48 × 10^{2}

**Answer: Option C **

.

12. The digits in a measured number that are known to be correct are called
**A.** accuracy digits

**B.** significant digits
**C.** error digits
**D.** precision digits

**Answer: Option B **

.

13. Which of the following is expressed in engineering notation?

**A.** 470 × 10^{5}
**B.** 82 × 10^{–2}
**C.** 9.1 × 10^{–6}
**D.** 14.7 × 10^{8}

**Answer: Option C **

.

14. The unit for frequency is the

**A.** hertz **B.** ampere

**C.** watt **D.** second

**Answer: Option A **

.

15. Add 21 mA and 8000 A and express the result in milliamperes.

**A.** 21.8 mA
**B.** 218 mA
**C.** 29 mA

**D.** 290 mA

**Answer: Option C **

16. Dividing 24 ×

10^{11} by 3 ×
10^{4} equals

**A.** 8 × 10^{4}
**B.** 8 × 10^{7}
**C.** 8 × 10^{11}
**D.** 8 × 10^{15}

**Answer: Option B **

.

17. Pico is what relation to micro?

**A.** one-tenth **B.** one-hundredth

**C.** one-thousandth **D.** one-millionth

**Answer: Option D **

**XI - Ohm's Law **

1. "Half-splitting" is

**A.** a means for nuclear fuel cells to produce
electricity

**B.** a means of isolating a problem in a circuit

**C.** a means for reducing a high ac voltage to a low
dc voltage

**D.** a means of limiting current in a circuit

**Answer: Option B **

.

2. If doubling the voltage across a resistor doubles the current through the resistor then

**A.** the resistor value decreased
**B.** the resistor value did not change
**C.** the resistor value increased

**D.** it is impossible to determine the change in the
resistor value

**Answer: Option B **

.

3. If the voltage across a fixed value of resistance is increased five times, what does the current do?

**A.** It increases by a factor of five.

**B.** It decreases by a factor of five.

**C.** It stays the same.

**D.** Not enough information

**Answer: Option A **

.

4. If the resistance in a circuit with constant voltage increases, the current will

**A.** increase
**B.** decrease
**C.** stay the same

**D.** Not enough information

**Answer: Option B **

.

5.

What is the power in the given circuit?

**A.** 3.6 W
**B.** 35 W
**C.** 175 W
**D.** 245 W

**Answer: Option B **

6. What is the kilowatt-hour consumption of a 40 W lamp if it remains on for 1750 h?

**A.** 43.75 **B.** 70

**C.** 43,750 **D.** 70,000

**Answer: Option B **

(1,750 x 40)/1000 = 70 kilowatt-hour.

7. A damaged resistor
**A.** may appear burned

**B.** may have an increased
resistance value

**C.** may be checked with an
ohmmeter

**D.** All of the above

**Answer: Option D **

.

8. Power supplies differ from batteries in that

**A.** power supply output voltages are
ac and not dc

**B.** power supply voltages are not
stable

**C.** power supplies are low-current
devices

**D.** None of the above

**Answer: Option D **

.

9.

What is the resistor value in the given circuit?

**A.** 200
**B.** 1 k
**C.** 2 k
**D.** 4 k

**Answer: Option C **

.

10. If voltage across a resistance doubles
**A.** the current is halved

**B.** the resistance doubles
**C.** the current is unchanged
**D.** none of the above

**Answer: Option D **
11

.

What is the power in the given circuit?

**A.** 32 W

**B.** 80 W
**C.** 500 W
**D.** 16 kW

**Answer: Option A **

.

12. Ohm's law describes the mathematical relationship between

**A.** ohms, kilohms, and megohms
**B.** resistor size and resistor value
**C.** resistance, voltage, and current
**D.** none of the above

**Answer: Option C **

.

13. Energy is defined as the ability to
**A.** produce heat

**B.** produce light
**C.** produce sound
**D.** All of the above

**Answer: Option D **

.

14. What electromotive force would cause 20 A of current to flow through a 500 resistor?

**A.** 0.04 V
**B.** 2.5 V
**C.** 25.0 V
**D.** 10,000 V

**Answer: Option D **

.

15. The rate at which work is performed is called

**A.** current **B.** energy

**C.** power **D.** voltage

**Answer: Option C **

16. A battery's capacity to deliver power is measured in

**A.** kWh **B.** Ah

**C.** Wh **D.** Vh

**Answer: Option B **

.

17. Power supplies are regulated to prevent the output voltage from changing due to changes in the

**A.** line voltage
**B.** supply load
**C.** frequency

**D.** both line voltage and supply load

**Answer: Option D **

.

18.

What is the power in the given circuit?

**A.** 3.92 kW
**B.** 280 W
**C.** 28.6 W
**D.** 9.8 W

**Answer: Option D **

.

19. If current through a resistance is halved
**A.** the resistance is halved

**B.** the voltage is halved
**C.** the voltage doubles
**D.** none of the above

**Answer: Option B **

.

20. Ohm's law is a relationship between
**A.** voltage, current, and time
**B.** power, current, and resistance
**C.** resistance, time, and current
**D.** voltage, current, and resistance

**Answer: Option D **

If the voltage in the given circuit was cut in half, what would the current equal?

**A.** 10 mA
**B.** 30 mA
**C.** 60 mA
**D.** 90 mA

Answer: Option B