# Gibilisco - Electrical Units

20 �ntrebri | Total Attempts: 1660  Settings  • 1.
A positive electric pole
• A.

Has a deficiency of electrons.

• B.

Has fewer electrons than the negative pole.

• C.

Has an excess of electrons.

• D.

Has more electrons than the negative pole.

• 2.
An EMF of 1 V
• A.

Cannot drive much current through a circuit.

• B.

Represents a low resistance.

• C.

Can sometimes produce a large current.

• D.

Drops to zero in a short time.

• 3.
A potentially lethal electric current is on the order of
• A.

0.01 mA.

• B.

0.1 mA.

• C.

1 mA.

• D.

0.1 A.

• 4.
A current of 25 A is most likely drawn by
• A.

A flashlight bulb.

• B.

A typical household.

• C.

A utility power plant.

• D.

• 5.
A piece of wire has a conductance of 20 S. Its resistance is
• A.

20 Ω.

• B.

0.5 Ω.

• C.

0.05 Ω.

• D.

0.02 Ω.

• 6.
A resistor has a value of 300 Ω. Its conductance is
• A.

3.33 mS.

• B.

33.3 mS.

• C.

333 µS.

• D.

0.333 S.

• 7.
A span of wire 1 km long has a conductance of 0.6 S. What is the conductance of a span ofthis same wire that is 3 km long?
• A.

1.8 S

• B.

0.6 S

• C.

0.2 S

• D.

• 8.
Approximately how much current can a 2-kW generator reliably deliver at 117 V?
• A.

17 mA

• B.

234 mA

• C.

17 A

• D.

234 A

• 9.
A circuit breaker is rated for 15 A at 117 V. Approximately how much power does this represent?
• A.

1.76 kW

• B.

1760 kW

• C.

7.8 kW

• D.

0.0078 kW

• 10.
You are told that an air conditioner has cooled a room by 500 Btu over a certain period oftime. What is this amount of energy in kWh?
• A.

147 kWh

• B.

14.7 kWh

• C.

1.47 kWh

• D.

0.147 kWh

• 11.
Of the following energy units, the one most often used to define electrical energy is
• A.

The Btu.

• B.

The erg.

• C.

The foot-pound.

• D.

The kilowatt-hour

• 12.
The frequency of common household ac in the United States is
• A.

60 Hz.

• B.

120 Hz.

• C.

50 Hz.

• D.

100 Hz.

• 13.
Half-wave rectification means that
• A.

Half of the ac wave is inverted.

• B.

Half of the ac wave is cut off.

• C.

The whole ac wave is inverted.

• D.

The effective voltage is half the peak voltage.

• 14.
In the output of a half-wave rectifier,
• A.

Half of the ac input wave is inverted.

• B.

The effective voltage is less than that of the ac input wave.

• C.

The effective voltage is the same as that of the ac input wave.

• D.

The effective voltage is more than that of the ac input wave.

• 15.
In the output of a full-wave rectifier,
• A.

Half of the ac input wave is inverted.

• B.

The effective voltage is less than that of the ac input wave.

• C.

The effective voltage is the same as that of the ac input wave.

• D.

The effective voltage is more than that of the ac input wave.

• 16.
A low voltage, such as 12 V,
• A.

Is never dangerous.

• B.

Is always dangerous.

• C.

Is dangerous if it is ac, but not if it is dc.

• D.

Can be dangerous under certain conditions.

• 17.
Which of the following units can represent magnetomotive force?
• A.

The volt-turn

• B.

The ampere-turn

• C.

The gauss

• D.

The gauss-turn

• 18.
Which of the following units can represent magnetic flux density?
• A.

The volt-turn

• B.

The ampere-turn

• C.

The gauss

• D.

The gauss-turn

• 19.
A ferromagnetic material
• A.

Concentrates magnetic flux lines within itself.

• B.

Increases the total magnetomotive force around a current-carrying wire.

• C.

Causes an increase in the current in a wire.

• D.

Increases the number of ampere-turns in a wire.

• 20.
A coil has 500 turns and carries 75 mA of current. The magnetomotive force is
• A.

37,500 At.

• B.

375 At.

• C.

37.5 At.

• D.

3.75 At. Back to top