William Gilbert
The earliest ideas of charge were the result of experiments by:
newtons
Common units of electrical force are:
lack of electrons
A positive charge means:
are charged with respect to the earth
Lightning is formed when clouds:
the sea, air, metals
Charges exist in:
has essentially no free electrons
An insulator is a material that:
conduction
Charges may be transferred by:
large quantities of charge
A storage battery will conduct:
true
An instrument to measure charge is called an electroscope.
battery
A _____ provides a steady flow of charge to the load connected to its terminals.
Coulomb
In 1787, __________ discovered a relationship between charge, their separation, and the force between the two charges.
repel; attract
Coulomb’s law indicates that like charges ______ and unlike charges ______
increases
Coulomb’s law also indicates that the force between charges _______ as their separation is decreased.
force
negative charge
positive charge
conductor
insulator
negative charge
positive charge
conductor
insulator
1. push or pull
2. result of an excess of electrons
3. result of a deficit of electrons
4. object with abundant free electrons
5. object with few free electrons
2. result of an excess of electrons
3. result of a deficit of electrons
4. object with abundant free electrons
5. object with few free electrons
wand contains relatively few free electrons, and the discharge period is short: the battery produces abundant charges and the discharge period is long
The flow of electrical charge from a battery differs from discharging a glass wand because the:
field
The force experienced by a unit test charge is a measure of the strength of an electric:
unit positive test charge
Conventionally, the field strength around a charged object is the direction of the force acting on a
Coulomb’s
The force between two point charges is described by _____ law.
charge
The difference in _____________ between clouds and earth frequently gives rise to lightning.
true
Oceanic electric fields produce electric currents
Gilbert
The early experiments with static charges were done by:
electrons
A negatively-charged object has an excess of
increases
The force between charged objects decreases when their separation
1 N
If the force is 4 newtons between two charged spheres separated by 3 centimeters, calculate the force between the same spheres separated by 6 centimeters.
1 N/C
Calculate the electric field strength where a test charge of 2 coulombs is repelled by a force of 2 newtons.
outer electrons of elements in good conductors are loosely held and are able to migrate readily
What characteristic does a good conductor possess?
unit positive
By definition the direction of a field vector is the direction of the force on a ______ charge.
capacitor
A device that stores electric energy is a
potential
An electric field produces the tendency for a charge to do work. This tendency is called
true
The flow of electric charge is called current.
ampere
The unit of current is the
Law of Conservation of Charge
The fact that electric charges return to the source of the current is an example of:
field
The region around a charged object is an electric _____.
lightning
An example of a natural electric field is
does not
A type of material that __ conduct charges is an insulator.
positive
A deficit of electrons produces a ____ charge.
false
Mass is equal to charge.
true
Newton’s law of gravitational attraction has the same form as Coulomb’s law.
true
Potentials and electric fields both result from electrical charges
true
A battery is a chemical storage container producing electrical potential.
false
Oceans do not have electric currents
true
Both the field and the potential between two charged parallel plates are due to charges on the plates.
false
The charge on a capacitor can be discharged by connecting the plates with an insulator.
2,400 V/m
Calculate the electric field strength between two parallel plates separated by 0.50 cm, across which is a potential of 12 volts.
17 N/C
Calculate the electric field strength at a point at which a test charge of 0.30 coulombs experiences a force of 5.0 newtons.
4 N
Calculate the mutual force of repulsion between two charged spheres 2 cm apart if the repulsive force for a 1 cm separation is 16 N.
field
A region of space in which a test charge experiences a force is a(n):
conductor
Any material possessing loosely held electrons that are free and capable of movements is a(n):
