Test 9 Flashcards
What early device was developed to store electric charge?
Leyden jar
What is the general term for a device that transforms the energy of an electric current into another useful form of energy?
load
What is the SI unit of resistance?
ohm
What device consists of one or more electrochemical cells connected in series to produce a single source of current?
battery
What device converts pulses of electricity into sound waves?
loudspeaker
What communication device uses electromagnets to reproduce messages by means of audible clicks?
telegraph
What is a material that allows current to flow through it with no resistance?
superconductor
Who built the first electrostatic generator?
Otto von Guericke
What is the transfer of an electric charge by direct contact between objects?
conduction
What device converts absorbed sunlight directly into electricity?
photovoltaic cell
What type of generator works by passing a conducting fluid through a magnetic field?
magnetohydrodynamic generator
What is an electric field with even strength throughout?
uniform
What is the method of magnetism in which an object is permanently magnetized by stroking a magnet against the object?
magnetizing by contact
What is a semiconductor device that produces light when a direct current is applied?
light-emitting diode
What is the line connecting all points where a compass needle points true north?
agonic
What is the imaginary line that circles Earth halfway between the two magnetic poles?
magnetic equator
What is the final attraction force between two charged objects when the distance is reduced to 1/5 of the original distance?
25 times the original force
What is a small, relatively inexpensive computer designed for use by one user at a time?
personal computer
What is a large, extremely powerful computer designed for rapidly performing complex calculations?
supercomputer
What allows a computer to communicate with the outside world or a user to communicate with the computer?
input/output device
What part of a computer controls all other systems of the computer?
central processing unit
What is the largest computer network?
internet