Power Engineering 4th Class Chapter 78

a

A basic law of electricity is, unlike charge attract each other and like charges: Choose one answer. a. Repel each other b. Hold each other c. Attract each other d. Neutralize each other e. Amplify each other

c

A conductor's resistance is a) directly proportional to its cross-sectional area b) directly proportional to its diameter c) inversely proportional to its cross-sectional area d) not affected by the cross-sectional area e) measured in micro-Newtons

a

A conductor's resistance is a) directly proportional to its length b) directly proportional to its diameter c) inversely proportional to its length d) not affected by the cross-sectional area e) measured in micro-Newtons

b

A material that conducts electrical current is called a) a volt b) a conductor c) a circuit d) an electromotive force e) a conduit

b

A material that conducts electrical current is called: Choose one answer. a. An insulator b. A conductor c. A circuit d. Wire e. A conduit

d

An electrical device that is designed to start and stop currents flow is the: Choose one answer. a. Power supply b. Fuse c. Circuit breaker d. Switch e. Resistor

d

An open circuit is one in which: Choose one answer. a. A switch is closed b. The current flows through the resistance c. The wires are bare d. A switch is open e. Voltage may exit

e

Atoms that have greater numbers of electrons in the outer shell are: Choose one answer. a. Positively charged b. Good conductors c. Poorinsulators d. Neutrally charged e. Poor conductors

a

Current flow is a) proportional to the applied voltage b) proportional to the resistance c) reversed by a resistance d) increased by a decrease in applied voltage e) inversely proportional to the applied voltage

c

Current flow is inversely proportional to the a) voltage b) amperage c) resistance d) wattage e) conductance

a

Electrical power can be determined by the formula: Choose one answer. a. P = E x I b. I = E x R c. E = I x R d. R = E x I e. P = I x R

b

Electrons are negatively charged particles: Choose one answer. a. Flowing through the atom's center b. Orbiting about the nucleus of an atom c. Firmly attached to the neutrons of an atom d. That can easily flow through insulators e. That seek open circuits

b

Equivalent resistance is decreased a) when voltage is decreased b) when a circuit is in parallel c) if the amperage is increased d) when a circuit is in series e) when a circuit is opened

a

If an electrical _____ is placed across a conductor, the electrons will drift from the negative end towards the positive end of the conductor. Choose one answer. a. Potential b. Current c. Resistance d. Wire e. Meter

d

If the power dissipated by a resistor is 1.2 kW when supplied with 110 V, the amperage will be _____ A. Choose one answer. a. 91.666 b. 0.11 c. 19.006 d. 10.91 e. 132

c

In an atom the electrons a) orbit around each other b) are repelled by the neutrons c) are attracted to the protons d) are large in size when compared to the protons e) orbit only the neutrons

c

In an equivalent circuit developed from a multi-resistor series circuit a) the resistance will be the reciprocal sum of the original resistances b) voltage drop will be the same as for each of the original resistances c) the sum of voltage drops across the original resistances will be equal to the voltage drop of the equivalent circuit d) original circuit resistances will each have to be the same as the equivalent resistance e) amperage flowing will be different than the original circuit amperage flowing through each resistance

a

Most conductors tend to a) increase in resistance with increase in temperature b) decrease in resistance with increase in temperature c) shrink when heated d) melt when voltage is applied e) oscillate when voltage is applied

c

Since the discovery of electrons, it has been determined that electrons are a negative charge and flow from a) positive to negative b) north to south c) negative to positive d) a lower potential to a higher potential e) the battery to the source

c

The EMF of an electrical circuit may be provided by: Choose one answer. a. The load b. The circuit resistance c. A battery d. The current e. The conductors

b

The equivalent resistance of three resistances of 10, 25 and 50 Ω connected in parallel is _____ Ω. Choose one answer. a. 0.16 b. 6.25 c. 85 d. 18.75 e. 8.5

b

The flow of electrons in a uniform direction is called a) voltage drop b) electrical current flow c) potential difference d) electromotive force e) direct current

a

The opposition, a device or material offers to the flow of electric current, is known as: Choose one answer. a. resistance b. conductance c. voltage drop d. insulation e. counter EMF

e

The purpose of having an upward movement of a switch handle to close the switch is: Choose one answer. a. To have the handle out of the way b. To meet the requirements of the electrical codes c. Because it is easier to operate when opening the switch d. It indicates the condition of the circuit e. To prevent the switch from closing due to gravity

a

The total equivalent resistance of three resistances in a series circuit can be given as: Choose one answer. a. R1 + R2 + R3 b. (1/R1) + (1/R2) + (1/R3 ) c. (R1/1) + (R2/2) + (R3/3) d. R1 x R2 x R3 e. (R1 + R2 + R3) / 3

c

The unit for opposition to current flow is the: Choose one answer. a. Volt b. Ampere c. Ohm d. Watt e. Newton

c

The voltage drop across a 20 Ω resistor with 10 A flowing would be _____ V. Choose one answer. a. 2 b. 0.5 c. 200 d. 20 e. 150

e

The voltage required to be supplied to a 12 kW motor drawing 24 A is: Choose one answer. a. 5 kV b. 50 kV c. 288 v d. 2 kV e. 500 V

e

The voltage required to force a current of 15 A through a resistance of 5 Ω will be _____ V. Choose one answer. a. 0.33 b. 3 c. 7.5 d. 33 e. 75

a

Three resistances of 20, 50 and 80 Ω make up a series circuit. The supply voltage is 400 V. The current flowing would be: Choose one answer. a. 2.67 A b. 20 A c. 8 A d. 5 A e. 0.375 A

b

Under normal circumstances, the heat produced by the electrical wires of a circuit is very small due to the a) large diameter of the conductor b) low resistance of the conductor c) long length of the conductor d) insulation wrapped around e) small diameter of the conductor

a

What is the composition of an atom? a. Protons and neutrons in the nucleus and electrons in the shell. b. Electrons and neutrons in the nucleus and protons in the shell. c. Electrons and nucleus in the neutron and protons in the shell. d. Protons and electrons in the nucleus and neutrons in the shell.

e

When 1 ampere of current flows through a resistance by the application of 1 volt the resistance will be 1: Choose one answer. a. Watt b. Joule c. Kilowatt d. Ampere e. Ohm

a

When a number of electrons pass a given point over a specific time period the energy may be referred to as a) an ampere b) voltage c) an ohm d) power or watts e) electromotive force

d

_____ current flow is from positive to negative. Choose one answer. a. Alternating b. Direct c. Static d. Conventional e. Electron