Conceptual Physics Chapter 23 Flashcards

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Questions and Answers

A coulomb of charge that passes through a 6-volt battery is given

6 newtons

6 joules (correct)

6 watts

6 ohms

6 amperes

Which statement is correct?

Voltage flows through an open or closed circuit

Charge flows in a close circuit (correct)

Resistance flows through an open circuit

Current is the primary cause of voltage

Electrons move in an electrical circuit

By being bumped by other electrons

By colliding with molecules

By interacting with an established electric field (correct)

Because the wires are so thin

None of the above

Heat a copper wire and its electric resistance

Increases Signup and view all the answers

Stretch a copper wire so that it is thinner and the resistance between it

Increases Signup and view all the answers

The primary source of electrons in an ordinary electric circuit is

The electric circuit itself Signup and view all the answers

The source of electrons lighting an incandescent AC lightbulb is

Atoms in the light bulb filament Signup and view all the answers

A woman experiences an electric shock. The electrons making the shock come from the

Woman's body Signup and view all the answers

In a common DC circuit, electrons move at speeds of

A fraction of a centimeter per second Signup and view all the answers

When a light switch is turned on in a DC circuit, the average speed of electrons in the lamp is

Less than 1 cm/s Signup and view all the answers

Modern automobile headlights are connected in

Parallel Signup and view all the answers

There are electrons in the filament of the AC lamp in your bedroom. When you turn on the lamp and it glows, the glowing comes from

The same electrons Signup and view all the answers

A 100-watt lamp glows brighter than a 25-watt lamp. The electrical resistance of the 100-watt lamp must be

Less Signup and view all the answers

In an electric circuit, the safety fuse is connected to the circuit in

Series Signup and view all the answers

When a pair of 1-ohm resistors are connected in series, their combined resistance is

2 ohms, and when in parallel, 1/2 ohm Signup and view all the answers

A capacitor is used to store

Both charge and energy Signup and view all the answers

The number of electrons delivered daily to an average American home by an average power utility in the mid 1980s was

Zero Signup and view all the answers

Two lamps, one with a thick filament and one with a thin filament, are connected in series. The current is greater in the lamp with the

The same in each lamp Signup and view all the answers

Two lamps, one with a thick filament and one with a thin filament, are connected in parallel to a battery. The voltage is greatest across the lamp with the

Both voltages are the same Signup and view all the answers

Two lamps, one with a thick filament and one with a thin filament of the same material, are connected in parallel to a battery. The current is larger in the lamp with the

Thick filament Signup and view all the answers

Compared to the resistance of two resistors connected in series, the same two resistors connected in parallel have

Less resistance Signup and view all the answers

If you plug an electric toaster rated at 110 V into a 220-V outlet, the current in the toaster will be about

Twice what it should be Signup and view all the answers

When a 60-watt light bulb is connected to a 120-volt source the current in the light bulb is

0.5 A Signup and view all the answers

If 0.8 A of current flows through a light bulb connected to a 120 V outlet, the power consumed is

96 W Signup and view all the answers

The headlights, radio, and defroster fan in an automobile are connected in

Parallel with a switch for each Signup and view all the answers

Compared to the filament thickness of a 60 W light bulb, the filament of a 100 W light bulb will be

Thicker Signup and view all the answers

Compared to a single lamp connected to a battery, two identical lamps connected in series to the same battery will carry

Less current Signup and view all the answers

Compared to a single lamp connected to a battery, two lamps connected in parallel to the same battery will carry

More current Signup and view all the answers

An electric heater is rated at 300 W when used in a 110-V circuit. The safety fuse in the circuit can handle 15 A of current. How many heaters can be safely operated in the circuit?

5 Signup and view all the answers

A heater uses 20 A when used in a 110-V line. If electric power costs 10 cents per kilowatt hour, the cost of running the heater for 10 hours is

$2.20 Signup and view all the answers

Connect a pair of lamps in series and you draw current from the connected battery. Connect the same lamps in parallel and you draw

More current Signup and view all the answers

Three resistors, 1-ohm, 2-ohm, and 3-ohm are connected in parallel. If they were connected in series instead their equivalent resistance would be

11 times as great Signup and view all the answers

The ratio of the potential difference across a metallic conductor to the current in the conductor is known as

Resistance Signup and view all the answers

What condition must exist between two points in a conductor in order to maintain a flow of charge?

None of the above choices are correct Signup and view all the answers

Study Notes

Electric Current Concepts

A coulomb of charge passing through a 6-volt battery provides 6 joules of energy.
Charge must flow in a closed circuit; voltage can exist in both open and closed circuits.
Electrons in an electric circuit primarily move due to interaction with an established electric field.
Heating a copper wire increases its electric resistance.
Stretching a copper wire results in increased resistance due to its reduced thickness.

Sources and Flow of Electrons

The primary source of electrons in an electric circuit is the circuit itself (e.g., batteries).
Electrons illuminating an incandescent light bulb originate from atoms in the filament.
Electric shocks experienced by individuals are due to electrons from their bodies.

Movement and Speed of Electrons

In common DC circuits, electrons move at speeds of a fraction of a centimeter per second.
When a light switch is engaged, the average speed of electrons in a lamp is less than 1 cm/s.

Circuit Configurations

Modern automobile headlights are wired in parallel for consistent brightness.
When a lamp glows, it is due to the same electrons that flow through the circuit, not different ones.
A higher wattage lamp (100-watt) has lower resistance compared to a lower wattage lamp (25-watt).

Current and Resistance in Resistors

Safety fuses are incorporated in series with the electrical circuit to protect against overload.
Two 1-ohm resistors in series yield a total resistance of 2 ohms; in parallel they give 0.5 ohms.
Capacitors are capable of storing both charge and energy.

Power Consumption and Safety

In the mid-1980s, average daily electron delivery to an American home was in the billions.
Comparing filament thickness, a 100-watt bulb has a thicker filament than a 60-watt bulb.
The voltage across parallel-connected lamps remains constant, regardless of filament thickness.

Electrical Ratings and Calculations

If a toaster rated at 110 V is plugged into a 220 V outlet, the current will be about twice what it is intended to be.
A 60-watt bulb connected to a 120-volt source draws 0.5 A of current.
A light bulb drawing 0.8 A from a 120 V outlet consumes 96 watts of power.

Current Flow in Parallel and Series

Automotive accessories like headlights and radios are connected in parallel with individual switches for control.
In a series configuration, current is the same across all components while it varies in parallel circuits.
Connecting identical lamps in series reduces the overall current compared to a single lamp.

Resistance in Series vs. Parallel

Two identical lamps in parallel draw more current than one lamp in series due to available voltage across both.
In a series connection, the equivalent resistance of three resistors (1-ohm, 2-ohm, and 3-ohm) would total 6 ohms, making it 9 times greater than their parallel configuration.

Concepts of Voltage and Current

The ratio of potential difference (voltage) to current is known as resistance.
For charge flow in a conductor, no special conditions like a magnetic field or a high resistance need to be present—just a potential difference.

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Test your knowledge of electric current concepts from Chapter 23 of Conceptual Physics. This quiz includes multiple-choice questions that focus on definitions and principles related to circuits and charges. Challenge yourself and enhance your understanding of how current behaves in different scenarios.