Question 1

A power supply provides a continuous 200 W to a load, with an efficiency of 80%. In a 24-hour period, how many KWh of energy does it consume?

Accepted Answer

A)  600 KWh 
B)  4.8 KWh 
C)  250 KWh 
D)  6 KWh 
A)  600 KWh 
B)  4.8 KWh 
C)  250 KWh 
D)  6 KWh

Question 2

Which of the following is NOT a correct formula for calculating power?

Accepted Answer

A)  P = V2/R 
B)  P = IV 
C)  P = I2R 
D)  P = VR 
A)  P = V2/R 
B)  P = IV 
C)  P = I2R 
D)  P = VR

Question 3

How much power does a 50 V amplifier use when 5 A of current flows through it?

Accepted Answer

A)  250 mW 
B)  10 W 
C)  250 W 
D)  100 mW 
A)  250 mW 
B)  10 W 
C)  250 W 
D)  100 mW

Question 4

Convert 0.072 W to mW.

Accepted Answer

A)  0.000072 mW 
B)  72 mW 
C)  7.2 mW 
D)  720 mW 
A)  0.000072 mW 
B)  72 mW 
C)  7.2 mW 
D)  720 mW

Question 5

Efficiency is determined by dividing the power output by the power input.

Accepted Answer

A) True 
 B)False

Question 6

A resistor which has a large physical size means:

Accepted Answer

A)  it can handle less power 
B)  it can dissipate more heat 
C)  it contains more carbon 
D)  it contains more resistance in ohms 
A)  it can handle less power 
B)  it can dissipate more heat 
C)  it contains more carbon 
D)  it contains more resistance in ohms

Question 7

The collision of electrons when passing through resistance results in energy loss given off as:

Accepted Answer

A)  watts 
B)  light 
C)  heat 
D)  voltage 
A)  watts 
B)  light 
C)  heat 
D)  voltage

Question 8

Power is measured in:

Accepted Answer

A)  Amperes 
B)  Watts 
C)  Joules 
D)  Energy 
A)  Amperes 
B)  Watts 
C)  Joules 
D)  Energy

Question 9

-Given the circuit in Figure 4-2, the power delivered to the lamp is:

Accepted Answer

A)  1.0 W 
B)  12 W 
C)  120 W 
D)  1.2 W 
A)  1.0 W 
B)  12 W 
C)  120 W 
D)  1.2 W

Question 10

Energy is the ability to do work.

Accepted Answer

A) True 
 B)False

Question 11

The amount of voltage in a circuit is 50 V, while the current is 0.2 mA. Determine the power.

Accepted Answer

A)  250 W 
B)  0.01 W 
C)  2 W 
D)  10 W 
A)  250 W 
B)  0.01 W 
C)  2 W 
D)  10 W

Question 12

-Given the circuit in Figure 4-3, which of the following resistor power values would you use in the circuit?

Accepted Answer

A)  1 W 
B)  5 W 
C)  15 W 
D)  20 W 
A)  1 W 
B)  5 W 
C)  15 W 
D)  20 W

Question 13

The power rating of a resistor is related to .

Accepted Answer

A)  directly, the type of cooling used 
B)  directly, its surface area 
C)  indirectly, the type of material used 
A)  directly, the type of cooling used 
B)  directly, its surface area 
C)  indirectly, the type of material used

Question 14

Which of the following is a correct formula for calculating power?

Accepted Answer

A)  $P=\frac{V^{2}}{R}$ 
B)  $P=E V$ 
C)  $\mathrm{P}=\mathrm{WI}$ 
D)  $\mathrm{P}=\mathrm{IR} ^2$ 
A)  $P=\frac{V^{2}}{R}$ 
B)  $P=E V$ 
C)  $\mathrm{P}=\mathrm{WI}$ 
D)  $\mathrm{P}=\mathrm{IR} ^2$

Question 15

The power dissipated by a resistor doubles if the applied voltage doubles.

Accepted Answer

A) True 
 B)False

Question 16

A 12 V battery is connected to a 400 Ω load. If it supplied current for 1000 hours, what was its Ah rating?

Accepted Answer

A)  30 Ah 
B)  120 Ah 
C)  3 Ah 
D)  60 Ah 
A)  30 Ah 
B)  120 Ah 
C)  3 Ah 
D)  60 Ah

Question 17

How long would it take for a 60 W lamp to consume 30.24 kilowatt-hours of power?

Accepted Answer

A)  3 weeks 
B)  0.505 hours 
C)  3 hours 
D)  21 hours 
A)  3 weeks 
B)  0.505 hours 
C)  3 hours 
D)  21 hours

Question 18

What is the total dissipated power from two series-connected 100 W lamps?

Accepted Answer

A)  10 kW 
B)  50 W 
C)  100 W 
D)  200 W 
A)  10 kW 
B)  50 W 
C)  100 W 
D)  200 W

Question 19

The amount of current in a circuit is 10 mA, while the resistance is 1 kΩ. Determine the power.

Accepted Answer

A)  0.0001 W 
B)  10 W 
C)  100 W 
D)  0.1 W 
A)  0.0001 W 
B)  10 W 
C)  100 W 
D)  0.1 W

Question 20

If a 12 Ω draws 1 A of current, what should be its wattage rating?

Accepted Answer

A)  1/4 W 
B)  1.2 W 
C)  3/4 W 
D)  12 W 
A)  1/4 W 
B)  1.2 W 
C)  3/4 W 
D)  12 W

Exam 4: Energy and Power

A power supply provides a continuous 200 W to a load, with an efficiency of 80%. In a 24-hour period, how many KWh of energy does it consume?

Which of the following is NOT a correct formula for calculating power?

How much power does a 50 V amplifier use when 5 A of current flows through it?

Convert 0.072 W to mW.

Efficiency is determined by dividing the power output by the power input.

A resistor which has a large physical size means:

The collision of electrons when passing through resistance results in energy loss given off as:

Power is measured in:

-Given the circuit in Figure 4-2, the power delivered to the lamp is:

Energy is the ability to do work.

The amount of voltage in a circuit is 50 V, while the current is 0.2 mA. Determine the power.

-Given the circuit in Figure 4-3, which of the following resistor power values would you use in the circuit?

The power rating of a resistor is related to .

Which of the following is a correct formula for calculating power?

The power dissipated by a resistor doubles if the applied voltage doubles.

A 12 V battery is connected to a 400 Ω load. If it supplied current for 1000 hours, what was its Ah rating?

How long would it take for a 60 W lamp to consume 30.24 kilowatt-hours of power?

What is the total dissipated power from two series-connected 100 W lamps?

The amount of current in a circuit is 10 mA, while the resistance is 1 kΩ. Determine the power.

If a 12 Ω draws 1 A of current, what should be its wattage rating?

Quantities and Units

Voltage, Current, and Resistance

Ohms Law

Series Circuits

Parallel Circuits

Series-Parallel Circuits

Circuit Theorems and Conversions

Branch, Loop, and Node Analyses

Magnetism and Electromagnetism

Introduction to Alternating Current and Voltage

Capacitors

Inductors

Transformers

Rc Circuits

Rl Circuits

Rlc Circuits and Resonance

Passive Filters

Circuit Theorems in Ac Analysis

Time Response of Reactive Circuits

Three-Phase Systems in Power Applications

Filters