Physics Exam 4

If you use 10 J of work to push a coulomb of charge into an electric field, its voltage with respect to its starting position is

10 V

Two charges separated by one meter exert 1-N forces on each other. If the charges are pushed to 1/4 meter separation, the force on each charge will be

16 N.

Superconductors are noted for their

absence of electric resistance.

When there is a change in the magnetic field in a closed loop of wire

all of these

Rapid change of a magnetic field induces

an electric field.

If a steady magnetic field exerts a force on a moving charge, that force is directed

at right angles to the direction of the motion

Like kinds of magnetic poles repel while unlike kinds of magnetic poles

attract.

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.

Electrons are made to flow in a wire when there is

a potential difference across its ends.

The unit of electric charge, the coulomb, is the charge on

a specific large number of electrons

A capacitor is used to store

both charge and energy.

Electrons move in an electrical circuit

by interacting with an established electric field.

To say that electric charge is conserved is to say that electric charge

can be neither created nor destroyed.

In an ac circuit, the electric field

changes magnitude and direction with time

Normally a small party balloon charged to several thousand volts will have a relatively small amount of

charge and energy.

Electric potential, measured in volts, is the ratio of electric energy to amount of electric

charge.

An ampere is a unit of electrical

current.

An electron is shot through a spot somewhere between the ends of a horseshoe magnet. The electron

direction is changed.

Magnetic domains normally occur in

iron

To say that an object is electrically polarized is to say

its charges have been rearranged.

Charge carriers in a metal are electrons rather than protons because electrons are

loosely bound

Electromagnetic induction occurs in a coil when there is a change in

magnetic field intensity in the coil

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

more current.

A 10-ohm resistor has a 5-A current in it. What is the voltage across the resistor?

more than 20 V

The source of all magnetism is

moving electric charge.

If you comb your hair and the comb becomes positively charged, then your hair becomes

negatively charged.

A main difference between gravitational and electric forces is that electrical forces

repel or attract.

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

resistance.

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

series

On some early automobiles both headlights went out when one bulb burned out. The headlights must have been connected i

series

The primary source of electrons in an ordinary electrical circuit is

the electrical circuit itself.

Two protons attract each other gravitationally and repel each other electrically. By far the greater force is

the electrical repulsion.

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

the same in each lamp.

A circuit is powered with a battery. Charge flows

through both the battery and the rest of the circuit.

A device that transforms mechanical energy into electrical energy is a

generator

Alternating current is normally produced by a

generator

The electric power of a lamp that carries 2 A at 120 V is

240 watts.

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

6 joules.

A 60-W light bulb and a 100-W light bulb are connected in series to a 120 V outlet. Which light bulb has more current in it?

Both have the same current.

Voltage can be induced in a wire by

Choices A, B, and C are all true.

The metal detectors that people walk through at airports operate via

Faraday's law

Every proton in the universe is surrounded by its own

electric field and gravitational field.

Which force binds atoms together to form molecules?

electrical

In an electrically neutral atom the number of protons in the nucleus is equal to the number of

electrons that surround the nucleus

A conductor differs from an insulator in that a conductor

none of these

Which pole of a compass needle points to a south pole of a magnet?

north pole

Outside a magnet, magnetic field lines are conventionally drawn from

north to south

Two charged particles held close to each other are released. As they move, the force on each particle increases. Therefore, the particles must have

opposite signs.

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

parallel with a switch for each.

Strip electrons from an atom and the atom becomes a

positive ion

When the distance between two charges is halved, the electrical force between the charges

quadruples.