Test 7 Flashcards
What is the rate of electric charge flow?
current
What is the region of concentrated magnetism at the end of a magnet?
pole
A balloon is rubbed with a wool cloth and sticks to a wall. Why can the balloon stick to the wall?
electric charge increases
The reciprocal of the total resistance of a _______ circuit equals the sum of the reciprocals of the resistance of the individual resistors.
parallel
What moves when charge flows through an electrolyte?
ions
Changing the charge of one object ___________ changes the attraction or repulsion between it and another object.
proportionately
What happens to resistance as the diameter of a conductor increases?
decreases
What is the orientation of the lines of flux when the inclination at the magnetic poles is 90 degrees?
vertical
What process imparts electric charge at a distance without direct contact between objects?
induction
In a parallel circuit, the voltage of each branch must be the ______ as the voltage of the circuit as a whole.
same
What is the Si unit of current?
ampere
What are used to indicate the direction and strength of a magnetic field?
lines of flux
What happens to the total current flowing in a parallel circuit when more branches are added?
increases
What value equals the product of voltage and current in an electric current?
power
What term describes a substance that has several unpaired electrons per atom and is strongly attracted to magnets?
ferromagnetic
What is the imaginary line that circles Earth halfway between the two magnetic poles?
magnetic equator
An electromagnet’s coil has 50 loops. What will happen to the strength of the electromagnet if another 50 loops are added?
quadruples
What circuit-protection device uses a narrow strip of metal to prevent excessive current through a circuit?
fuse
What is the most important factor affecting the ease of current flow through a wire?
material
What method of magnetism is used when a needle is magnetized by holding a magnet near the needle?
magnetizing by induction
How do two like charges interact when they are brought close to each other?
repel
If one wire is twice as long as another wire that is otherwise identical, what is true about their resistance?
the longer wire has greater resistance
Which of the following is the resistance of a magnet to being demagnetized by another magnetic field?
coercivity
What is the work per unit charge done to move electric charges between different parts of an electric field?
voltage
What device transforms the energy of an electric current into another useful form of energy?
load
What kind of electric field has an equal strength throughout?
uniform
What force causes an electric charge moving through a magnetic field to deviate from its original path?
deflecting
What is the extent of a planet’s magnetic field in space?
magnetosphere
What term describes an object with an equal number of positive and negative charges?
neutral
What is an object capable of attracting materials by a magnetic force?
magnet
What is the Si unit of resistance?
ohm
What are the two belts of charged particles located above Earth’s equator that protect Earth from the solar wind?
Van Allen radiation belts
material through which current does not easily flow
insulator
material that allows current to flow through it with no resistance
superconductor
electrical device designed to hinder current flow
resistor
material through which current flows easily
conductor
the Earth’s “north-seeking” pole
south magnetic pole
A simple device that uses the laws of electrostatics to detect small electric charges
electroscope
A material whose domains strongly resist changes in the direction of its magnetic field is described as magnetically ______.
hard
a device that opens or closes a circuit
switch
A circuit that contains a complete path for electrons to flow through is a(n) ______ circuit.
closed
The extent to which a material can absorb or channel lines of flux is _________.
permeability
The process of diverting unwanted electric charge directly into the earth is ______.
grounding
The law that relates current, voltage, and resistance is ____ law.
Ohm’s
A substance that has no unpaired electrons and is slightly repelled by either pole of a magnet is a _______ substance.
diamagnetic
F=k qq/r^2
law of electric force
V=IR
Ohm’s law
1/R= 1/R +1/R + 1/R ….
parallel circuit
P= VI
power of electric current
In a _____ circuit, added bulbs increase total resistance, but in a parallel circuit, added bulbs decrease total resistance.
series
If a magnet is cut in half to separate the poles, ______ align to make a north and a south pole on both halves.
domains
R= R + R + R ….
series circuit
