Science Exam Flashcards
a branch of the study of electricity that deals with the behavior and motion of electrons in a vacuum or in semiconductors
electronics
negative electrode of a vacuum tube
cathode
positive electrode of a vacuum tube
anode
glass tube containing electrodes sealed in a vacuum
vacuum tube
Early experimenters with vacuum tubes knew something was crossing the gap between electrodes in a vacuum, so they named them ______
cathode rays
designed so that the cathode rays would miss the anode and strike the end of the glass tube instead
cathode-ray tube (Crookes tube)
special type of vacuum tube to study cathode rays
cathode-ray tube (Crookes tube)
cathode-ray tube designed to generate x-rays
x-ray tube
tube designed to generate rays that were originally unknown
x-ray tube
The production of an electric current in a vacuum using a heated cathode
thermionic emission (Edison effect)
a vacuum tube in which current only flows one direction; has 2 electrodes
diode
a simple vacuum tube consisting of two electrodes
diode
a vacuum tube with three electrodes
triode
_____ acts as a very fast electronic switch
triode
a material that is neither a good conductor nor a good insulator
semiconductor
process where you can increase the number of holes or electrons by replacing some of the atoms of the semiconductor with atoms of another element
doping
material with extra electrons that are free to move
n-type semiconductor
material with extra holes lacking negative charge
p-type semiconductor
semiconductor device that, like a vacuum-tube diode, allows current to pass in only one direction
semiconductor diode
True or false: a p-n junction allows current to flow in only one direction
true
a semiconductor device that can perform the same functions as a vacuum-tube triode, such as acting as a “switch” and amplifying weak signals
transistor
A semiconductor device that produces electric current through the separation of charges through light
photovoltaic cell
devices that consist of solid crystals of semiconductor
solid-state devices
the most common type of transistor used today
FET (field-effect transistor) - found in computer chips
semiconductor diode that emits visible light when an electric current is applied
LED
device consisting of a single piece of semiconductor containing an entire electronic circuit
integrated circuit (chip)
three benefits of integrated circuits
- smaller
- cheaper
- more reliable
True or false: the effects of the transistor revolution are far greater than the effects of the integrated-circuit revolution.
false - it is the opposite
device that processes information using electronic circuits
computer
pieces of information
data
America’s first mass-produced computer
UNIVAC 1
first general-purpose electronic computer
ENIAC
The modern computer era is said to have begun with the completion of ______
ENIAC
random variations that affect any signal
noise
data that can have any possible value within a specified range
analog data
data that can have only certain values within a range
digital data
practically all modern electronic computers are _____ computers
digital
number system based on powers of 2
binary number system
number system based on powers of 16
hexadecimal number system
computer coding system upon which most other common coding systems are based
ASCII
a device that produces a single binary output based on one or more binary inputs
logic gate
the physical components of a computer
hardware
The “brain” of the computer; controls all the other systems of the computer, performs calculations, and executes the commands needed to accomplish specific tasks
CPU (central processing unit)
a single chip containing a complete CPU
microprocessor
the system of a computer that allows the CPU to store programs and information
memory
memory used by a computer to store information temporarily
RAM
memory used to store basic information that a computer needs to start and for flash memory
ROM
computer hardware used for permanent storage of information
mass storage device
a device that allows the CPU to communicate with the outside world
input/output device (I/O device)
a circuit board that connects all the computer’s components
motherboard
stored information and instructions that direct a computer to perform certain tasks
software
a single piece of software that directs a computer to perform a certain task
program
the worldwide computer network
internet
a large, powerful computer designed for rapidly performing complex calculations
supercomputer
a versatile, computer-directed machine that can be programmed to perform different tasks
robot
type of memory that flash memory would use
ROM
method of real-time communication
chat
system of using the internet to access remote computer resources, usually to store information
cloud computing
small, relatively inexpensive computer designed for one user at a time
PC (personal computer)
single piece of software that directs the computer to do a certain task
program
SI unit of electric charge
Coulomb
some examples of mass storage devices are ____, ____, and _____
hard drives, optical discs, and flash memory
connects multiple computers electronically, allowing information to be shared among them
computer networks
most software is written in ____
programming language
includes all the different programs that direct the computer to perform specific tasks for the user
application software
Most system software is part of the _____
operating system (OS)
the collection of programs that contain instructions for displaying words and images on the screen for the user to see, saving information on the disk drive, and detecting what the user types on the keyboard
operating system (OS)
computers that can be programmed to perform a variety of processing tasks
general-purpose computers
“serves” other computers by providing them with requested data
server
large computers designed to store and retrieve vast amounts of information
mainframes
the study of the nature, behavior, and uses of static electricity and related phenomena
electrostatics
a proton has a ____ charge
positive
an object with an equal number of positive and negative charges is ____
neutral
the simplest form of electricity
static electricity
electricity where the charges are stationary
static electricity
states that opposite charges attract each other but like charges repel each other
law of electric charges
the SI unit of electric charge
Coulomb
electric fields can be mapped by _____, which are arrows that indicate how a positive test charge in the field would move
lines of force
the method of charge transfer that is permanent is _____
conduction
the flow of charge from one place to another
current
the SI unit of voltage
volt
Electricity that flows first in one direction and then the other, reversing at regular intervals, is called _____
AC (alternating current)
the SI unit of current
amp
materials through which electricity flows easily
conductors
SI unit of resistance
ohm
four factors affecting resistance
type of material, diameter of conductor, length of conductor, temperature
material allows current to flow with no resistance
superconductor
what is Ohm’s law
V = IR
voltage = current x resistance
three parts of an electric circuit
source of current, conductors, load
device that opens and closes a circuit
switch
narrow strip of metal housed in a protective insulated case
fuse
occurs when electricity takes a shortcut avoiding the load
short circuit
an automatic switch that opens the circuit when current flowing through it exceeds a predetermined amount
circuit breaker
a circuit in which the loads are arranged so that the electric current flows through each load one after another
series
a circuit in which the loads are arranged in separate branches of the circuit and the current is divided among them
parallel circuit
regions of concentrated magnetism
poles
states that unlike poles attract each other, but like poles repel each other
law of magnetic poles
lines that indicate the direction and strength of the magnetic field
lines of flux
most important cause of magnetism in magnetic materials
electron spin
the extent to which a material can absorb or channel lines of magnetic flux
permeability
Lines connecting all points of 0 declination
agonic line
Lines connecting all points of 0 inclination
magnetic equator
ways to make a stronger electromagnet
add core, increase current, increase coils
electric charge always moves ____
to the outside of the object
surge of electricity from a cloud to the ground
lightning
modern device for storing static electric charge
capacitor
first electric light suitable for household use
incandescent lamp
three electric discharge lamps
fluorescent, CFL, neon lamp
device for converting electricity to back and forth motion
solenoid
electrical switch operated by an electromagnet
relay
device for converting pulses of electricity into sound waves
loudspeaker
Device that can increase or decrease voltage of electric current using electromagnetic induction
transformer
three ways to increase current based on electromagnetic induction
add coils, stronger magnet, more motion
the negative terminal of a battery
anode
the positive terminal of a battery
cathode
a group of aligned atoms having a single magnetic field
domain
substances with no unpaired electrons
diamagnetic
substances that are always slightly repelled by either pole of a magnet
diamagnetic
material weakly attracted to a magnet
paramagnetic
material with one unpaired electron
paramagnetic
materials that are strongly attracted to magnets
ferromagnetic
substances with several unpaired electrons
ferromagnetic
a device that produces a strong magnetic field when electricity passes through it
electromagnet
temperature at which a ferromagnetic material’s domains disappear
Curie point
a navigational device consisting of a magnet free to swing horizontally so that it always points north
magnetic compass
book published by William Gilbert about his findings on magnetism
De Magnete
the deviation of a compass from true north
angle of declination
a device that produces static electricity
electrostatic generator
a device for communicating over long distances by means of electromagnets
telegraph
the most important device for converting electricity into motion
electric motor
batteries arranged in ___ increase current
parallel
batteries arranged in ____ increase voltage
series
a generator in which a conducting fluid passes through a magnetic field at high speed
MHD generator
the amount a certain object hinders electron flow
resistance
energy divided by time
power
work per unit charge done to move electric charges between different parts of an electric field
voltage
