unit 8-10 physical science crossword **FINAL**

generator

a device that converts mechanical work or energy into electrical energy

ferromagnetic

characteristic of substances such as iron, nickel, and cobalt that exhibit the ability to acquire high magnetization

current

the time rate of flow of electric charge

electric charge

a fundamental property of matter that can be either positive or negative and gives rise to electric forces

electric current

has the formula I = q/t

protons

positively charged particles in the nuclei of atoms

direct current

electric current flowing in one direction, for example, electrons moving directionally from the negative (-) terminal toward the positive (+) terminal of a battery

Ohm's Law

has the formula V=IR

Ohm's Law

the voltage across 2 points is equal to the current flowing between the points times the resistance between the points

law of poles

Like poles repel; unlike poles attract

motor

a device that converts electrical energy into mechanical energy

Series Circuit

a circuit in which the same current flows through all the circuit elements

voltage

the amount of work it would take to move a charge between two points divided by the value of the charge

voltage

has the formula V=W/q

transformer

the device based on electromagnetic induction that increases or decreases the voltage or alternating current

Coulomb's law

states that the force of attraction or repulsion between two charged bodies is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them

declination

the angle between geographic (true) north and magnetic north

JJ Thomson

discovered the electron

atom

the smallest particle of an element that can enter into a chemical reaction

laser

an acronym for light amplification by stimulated emission of radiation; it produces coherent, monochromatic light

quantum

a discrete amount of energy

Chadwick and Rutherford

discovered neutrons

excited states

The energy levels above the ground state in an atom.

photon

a "particle" of electromagnetic energy

electron cloud model

the widely accepted model of the atom today

Heisenberg uncertainty principle

it is impossible to know a particle's exact position and velocity simultaneously

Neils Bohr

Rutherford's student who developed the theory that electrons orbit around the nucleus in set orbits and paths, which are known as energy levels

photoelectric effect

the emission of electrons that occurs when certain metals are exposed to light

quantum mechanics

The branch of physics that replaced the classical-mechanical view (that everything moved according to exact laws of nature) with the concept of probability.

line emission spectrum

A set of bright spectral lines of certain frequencies or wavelengths formed by dispersed light from a gas of a heated element. Each element gives a different set of lines.

principal quantum number

The numbers (n = 1, 2, 3, . . .) used to designate the various principal energy levels that an electron may occupy in a hydrogen atom.

Thomson

his model is known as the plum pudding model

rutherford

completed the gold foil experiment

radioactivity

The spontaneous process of nuclei undergoing a change by the emitting particles or rays.

mass number

given under its symbol in the periodic table

neutrons

electrically neutral particles

electrons

negatively charged subatomic particles

radioactive isotope

An isotope that undergoes spontaneous decay (disintegration).

chain reaction

Occurs when each fission event causes at least one or more fission events.

protons and neutrons

found inside the nucleus of an atom

critical mass

The minimum amount of fissionable material necessary to sustain a chain reaction.

nucleus

the central core of an atom

atomic mass

The weighed average mass of an atom of the element in naturally occurring samples

atomic number

The number of protons in the nucleus of an atom

atomic number

in isotopic notation, symbolized by the letter z

strong nuclear force

The short-range force of attraction that acts between two nucleons and holds the nucleus together.

nucleons

A collective term for neutrons and protons

mass number

the total number of nucleons

isotopes

Forms of nuclei of an element that have the same numbers of protons but differ in their numbers of neutrons.

carbon-14 dating

A procedure used to establish the age of ancient organic remains by measuring the amount of ^14C in a sample.

elementary particles

Particles coming from the nucleus that are not certain to be fundamental.

mass number

The number of protons plus neutrons in a nucleus;

plasma

A high-temperature gas of free electrons and positively charged ions.

half-life

The time it takes for half the nuclei in a given radioactive sample to decay.