physics
What are the two types of charges that objects may possess?
+ and -
calculate the force exerted between two charged objects separated by a distance of 0.6 m. One object has a charge of -5 C and the other has a charge of +2.0 C.
-2.5E11 N
With the "Falling-drop Method", which law did Millikan use to measure the charge of an electron?
Coulomb's Law
with the "Falling-drop Method", which law did Millikan use to measure the charge of an electron?
Coulomb's Law
What equation is this: FE= (k*q1*q2) / r2
Coulombs law
What variable do meters represent?
Distance
What variable do Coulombs represent?
Electrostatic Charge
what variable do Coulombs represent?
Electrostatic Charge
What makes a charged balloon stick to the wall?
Extra electrons on the surface of the balloon push away electrons in the wall, leaving a positively charged area.
In an electric field, Point A has more electric field lines moving through it than Point B. Which is true?
Point A will have a stronger Force, Point B is farther away and has a weaker Force
Charles Augustin de Coulomb named a law after him after he helped us better understand electrical charges. What instrument did he use for his research?
a torsion balance
which is most likely to form a negative ion?
an element from group 17
An electric field has-
both magnitude and direction
Electrostatic force F is directly proportional to:
both q1 and q2
What does the Law of Conservation of Charge state?
charges cannot be created nor destroyed, only transferred
The Electric Force is strongest when charges are...
close together
When distance increases, electrostatic force ____________; we call this relationship ____________ proportional
decreases;inversely
when distance increases, electrostatic force ____________; we call this relationship ____________ proportional
decreases;inversely
electrons in other materials are tightly bound to the atomic nuclei, and are not free to roam in the material. What are these materials called?
insulators
If two like charges are brought near each other, what type of energy will they have as they begin to repel?
kinetic energy
if two like charges are brought near each other, what type of energy will they have as they begin to repel?
kinetic energy
what is the fundamental rule for electrostatics?
like charges repel and opposites attract
in an electric field surrounding particles, field strength is greater where field lines are- (select all that apply)
longest, closer together
positive ions form when atoms_________valence electrons
lose
Two opposite charges are near each other. They will have a:
low electric potential energy
what is a semiconductor?
material that can move electrical charges as well as prevent the flow of electrical charges
What is an insulator?
material that cannot move electrical charges
what is an insulator?
material that cannot move electrical charges
What are the best conductors?
metals (copper, silver, and aluminum)
what happens when you touch a metal doorknob after rubbing your shoes on the carpet?
millions of electrons go from your finger into the doorknob
what charge does an electron have?
negative
J.J. Thomson used a cathode ray to show atoms are charged particles. What charge would the ray from the cathode have if the ray moved to the positive field? Why?
negative, because opposites attract
The distance between two charges doubles at the same time that the charge on each also doubles. What happens to the electric force?
no change
What are the best insulators?
plastics, ceramics, rubber, wool, wood and glass
When an atom loses a valence electron, it becomes a(n) _____________ ion.
positive
What types of charges attract?
positive and negative
if each of the charges doubles, what happens to the electric force?
quadruples
if the distance between two electric charges is reduced by half, what happens to the electrostatic force?
quadruples
if the distance between 2 charges doubles, what happens to the electrostatic force?
reduced by 1/4
Where can you find semiconductors?
silicon, computer chips and electronic circuits
the teacher rubbed two balloons with a piece of wool. What will happen when the balloons are brought near each other?
the balloons will repel each other
Label the parts of this atom correctly. (select all that apply)
the nucleus is positive; the orbiting electron is negative
Two like charged particles are held in place near each other. When the particles are released, what will most likely happen?
they will accelerate away from each other
two oppositely charged particles are held in place near each other. When the particles are released, what will most likely happen?
they will accelerate towards each other
true or false, Lighting is a form of static electricity.
true
Two charges separated by a distance of 1 meter exert a 20-N force on each other. If the charges are pulled to a 2 meter separation distance, the force on each charge will be
5 N
1 Coulomb is equivalent to
6 x 10^18 Charges
find the magnitude of the electrostatic force between two charges of 1.0 C each, which are 1.0 meter apart?
9 x 10^9 N
