Science TESTSSSS

The potential energy/charge=

Voltage

Electricity is the flow of

Electrons

All electrons have the same charge. T or F

True

Two wires are made up of the same material and are the same length. One is twice as thick as the other. Which has less resistance?

Thicker wire

Just as energy cannot be created or destroyed, electric charge also cannot be created or destroyed. T or F

True

The unit of charge is the

Coulomb

The negatively charged part of an atom is the

Electron

The flow of electric charge that transports energy from one place to another is

Electric current

The property of a material that prevents the flow of charged particles through it is

Electrical resistance

Electrical resistance is measured in a unit called an ohm. T or F

True

Electrons do not flow in a wire when a difference in "electrical pressure" exists. T or F

False

The positively charged part of the atom is the

Proton

An atom with a charge is called a/an

Ion

Which make(s) up the nucleus of an atom? Protons, Neutrons, Electrons

Protons, Neutrons

The gravitational force of an object is stronger than its electrical force. T or F

False

Like charges attract one another. T or F

False

The length of a wire does contribute to its resistance. T or F

False

The rate of electrical flow is measured in the

Ampere

Unlike charges repel one another. T or F

False

What? states that electrical force between two charged bodies is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

Coulomb's law

The amount of current in a circuit is directly proportional to the voltage across the circuit and inversely proportional to the resistance of the circuit. This is

Ohm's Law

A circuit in which electrical devices are connected so that the same electric current exists in all of them is a

Series circuit

What? is electrically charged particles that repeatedly reverse direction, vibrating in relatively fixed positions in a circuit.

Alternating current

In a What?, electrical devices are connected so that the same voltage acts across each one and any single one completes the circuit independently of all the others.

Parallel circuit

In What?, electrically charged particles flow in one direction only.

Direct current

The rate of energy transfer or rate of doing electric work is

Electric power

current =

Voltage / Resistance

For there to be a flow of electrons, there must be a difference in

Voltage.

"Electrical pressure" is a way to say

Voltage.

amps x volts =

Watts

If a break occurs anywhere in a series circuit with three lightbulbs, all the lightbulbs go out. T or F

True

If a break occurs anywhere in a parallel circuit with three lightbulbs, all the lightbulbs go out. T or F

False

As more lamps are connected to a series circuit, the overall current in the power source decreases. T or F

True

Household circuits are normally wired in series to decrease the risk of overload. T or F

False

If you add more branches to a parallel circuit, the overall resistance of the circuit decreases. T or F

True

Overloading in a parallel circuit can occur when too many branches are added, which decreases the overall resistance of the circuit. T or F

True

Fuses and circuit breakers can be used to prevent a circuit overload. T or F

True

When voltage across a circuit is tripled, the current in the wire also triples. T or F

True

When resistance of a circuit is tripled, the current in the wire also triples. T or F

False

When a battery is connected in a closed circuit, more current flows out of it than into it. T or F

False

Why don't birds get electrocuted when they sit on power lines?

The birds are not grounded; there is no difference in voltage for the current to flow.

What pattern is observed in the magnetic field of a current-carrying wire?

Concentric circles

What is the probable source of Earth's magnetic field?

Movement of electric charge in the Earth's core.

How many magnetic poles are there in a common bar magnet?

Two

Changing the magnetic field in a closed loop that is a conductor will induce current. T or F

True

If you break a magnet in half, the two pieces will no longer be magnetic. T or F

False

A magnetic domain is

a large cluster of iron atoms that have aligned with one another.

Why does rubbing one magnet with another magnet in straight lines help strengthen the magnetic field?

It helps line up the domains into proper alignment.

Most common magnets are made from alloys containing which three metals in various proportions?

iron, nickel, and cobalt

When iron filings are placed on a piece of paper over a magnet, the pattern they form shows the earth's magnetic field. T or F

False

The earth's magnetic field protects us from many cosmic rays. T or F

True

Electric meters that detect current are called

galvanometer

Most metals are not magnetic, but iron is. Why?

Most metals are without magnetic domains, whereas iron has domains.

The smallest magnet within an iron magnet is

each individual iron atom.

Why will dropping an iron magnet on a hard floor make it a weaker magnet?

Sudden changes in motion can jostle atoms out of alignment.

A wire lies by a strong magnet and is suddenly repelled by that magnet. This indicates that

an electric current just passed through the wire.

An electron generates a magnetic field when it -spins -travel through a wire -revolves around the nucleus -all of these

All of these.

Michael Faraday in England, and Joseph Henry in the United States, worked together to prove that electricity could be produced from magnetism. T or F

False

We've observed a magnet with only one pole. T or F

False

Trains that levitate at high speeds above the tracks make use of

superconducting magnets.

A magnetic field is produced by the motion of electric charge. T or F

True

A magnet is produced by the motion of charged particles. T or F

True

A current-carrying wire experiences a force when it is perpendicular to a magnetic field. T or F

True

An electric generator is actually a source of energy. T or F

False

The Earth itself is a giant magnet. True or False

True

When a current-carrying wire is in a magnetic field, the wire experiences greatest force when it is

at right angles to the field.

What is the basic difference between a generator and an electric motor?

A generator converts mechanical energy into electrical energy; a motor converts electrical energy into mechanical energy.

What commonly supplies the energy input to a turbine?

A moving fluid, often steam or flowing water.

What is induced by the rapid alternation of a magnetic field?

An electric field.

What is induced by the rapid alternation of an electric field?

A magnetic field.

What surrounds a stationary electric charge? A moving electric charge?

An electric field. An electric field and a magnetic field.

A galvanometer detects electric current. This device can be made into -an ammeter -a voltmeter -both of these -neither of these

Both of these.

An electric generator and an electric motor are

similar devices with input and output reversed.

A generator is used to light a lamp. The energy of the lit lamp comes from

whatever is used to turn the windings in the generator.

The Earth’s magnetic field helps to reduce the amount of

charged particles from outer space hitting its surface.

The physicist Maxwell, in the mid 1800s, discovered that electricity and magnetism connect to become

light.

A magnetic force acting on a beam of electrons can change its

direction.

A friend tells you that his bike frame is 100% aluminum so it'll never rust. How could you check if this is true?

Apply a magnet to the frame. If it sticks, there's likely iron in the frame.

Andy grew two inches taller last year. That is best described as a physical change. T or F

False

After a physical change, the molecules making up a substance are always the same. T or F

True

A branch of science that is the study of matter and the transformations it can undergo is

chemistry

In which of the following states of matter do attractions between particles no longer hold particles together, allowing particles to separate?

gas

A branch of scientific research that focuses on a greater understanding of how the world works is

basic research

Which of the following properties is/are physical?

state of matter

color

density

texture

hardness

At the microscopic level, solid, liquid, and gaseous phases are distinguished by how the submicroscopic particles hold together. T or F

False

Which of the following changes is/are chemical?

Answer,

a hot beaker cracking when rinsed in cold water

Correct answer:

fruit rotting

Correct answer:

autumn leaves changing color

Answer,

sweat evaporating from your skin

Answer,

chocolate melting

Correct answer:

baking bread

Which of the following changes is/are chemical?

a hot beaker cracking when rinsed in cold water

fruit rotting

autumn leaves changing color

sweat evaporating from your skin

chocolate melting

baking bread

fruit rotting

autumn leaves changing color

baking bread

Which of the following changes is/are chemical?

tearing a piece of paper in half

freezing water in an ice cube tray

rusting metal

shaping play-doh into a bowl

denting a car

lighting a match

rusting metal

lighting a match

At a What? level, atoms and molecules are unable to be observed directly with optical microscopes.

submicroscopic

Chemistry is involved in all other sciences. T or F

True

In which of the following states of matter are attractions between particles holding the particles together in some fixed three-dimensional arrangement?

solid

A solid at 25 degrees Celsius has stronger attractions among its submicroscopic particles than does a liquid substance at 25 degrees Celsius. T or F

True

The phase of matter in which atoms and molecules no longer move is the solid phase.

liquid phase.

gas phase.

None of the above are correct.

None of the above are correct.

A branch of scientific study that focuses on developing applications built upon basic research principles is

Correct answer:

applied research

Science progresses as scientists conduct research. T or F

True

At a What? level, matter is large enough to be seen, measured, and handled.

macroscopic

After a physical change, the attractions between molecules making up the substance are always the same. T or F

False

Which of the following is an example of an elemental formula?

O₃

What is the chemical name for the compound KCl?

potassium chloride

What is the chemical name for the compound CCL₄?

carbon tetrachloride