physics chapter 18 test
what is the unit for charge?
Coulomb or C
what is the charge of a single electron?
-1.6 x10-19 C
TRUE OR FALSE: an object that becomes grounded gains neutrons during the grounding process.
FALSE, neutron lives don't matter...
what do each of the variables in Coulomb's Law equation stand for?
K = a constant equal to 9x10^9 in air. It is a measure of air conductivity Q = the charges of two objects F = the electrical force between two objects D = the distances between the center of mass of two charged objects
in the physics and electrical charges world what does the term ground mean? and why is grounding important?
a ground has an infinite supply of electrons and is useful for balancing out the charge of any charged object to make it neutral. grounding is important because it causes neutralizes charges which could be dangerous in different situations.
what is an electric field?
an electric field is an area where the electrical forces act on a charged object.
a metal sphere is electrically neutral. it is touched by a positively charged metal rod. as a result, the metal sphere becomes charged positively. what occurs during the process? list all that apply.
electrons are transferred from the sphere to the rod. the metal sphere loses electrons. the overall charge of the system is conserved.
in charged objects, which subatomic particle is actually moving from object to object?
electrons. protons and neutrons are fixed to the nucleus and cannot move freely
what is electrostatic equilibrium?
electrostatic equilibrium is what is reached when the charges are balanced out and no longer move (meaning that they are not moving toward or away from each other).
what are the 3 different ways an object can become charged? how do they differ from one another?
friction - in contact and surfaces are being rubbed together. objects started out as being neutral and gain charge due to electron affinity induction - a charged object is brought near a non charged object but does not touch it. conduction - a charged object is touched to a non charged object and electrons are transferred.
a positively charged balloon is brought near a neutral conducting sphere as shown below. While the balloon is near, the sphere is touched (grounded). At this point, there is a movement of electrons. Electrons move ____.
into the sphere from the ground (hand)
what happens when a charged object comes into contact with a neutral object?
it is attracted to it since the electrons will move allowing for it to be attracted.
what does it mean for an object to be polarized?
it means that there is a positive charge on one side of the object and a negative charge found on the other side.
which statement best explains why a rubber rod becomes negatively charged when rubbed with fur?
molecules in the rubber rod have a stronger attraction for electrons than the molecules in the fur.
determine the quantity and type of charge on an object that has 3.62 x 1012 more protons than electrons.
positive because there are more protons multiply the number of protons by the charge of one proton and the answer is 5.8x10-7C.
8.25749 x 1017 protons and 5.26 x 1014 electrons; the charge on this object is ____ Coulombs.
positive because there are more protons. subtract number of electrons from the protons, then multiply by the charge of one proton. The answer is 0.13 C.
when is a electrical field positive and when is it negative?
positive- the vectors are pointed away from the charge negative- the vectors are pointed toward the charge arrows always point to the negative charge
a negatively charged balloon is brought near a neutral conducting sphere. as it approaches, charge within the sphere will distribute itself in a very specific manner. what does this look like?
the balloon does not touch the sphere meaning that the sphere remains neutral, but the electrons will be repelled to the other side of the sphere. the balloon is negative, the protons in the sphere attract to the balloon while the electrons repel from the balloon.
if the electrons move from the sweater to the balloon, which has a greater electron affinity? how can you tell?
the balloon does. electron affinity means that the object attracts electrons to itself so if the balloon gains a negative charge, that means the electrons traveled from the sweater to the balloon because it has a higher affinity for the electrons.
what's the difference between a conductor and an insulator?
the electrons found in a conductive material are more free to move around than those found in an insulative material.
define electrical force. is it a vector? what is it measured in? is it a contact force?
the force experienced by a charged object. this force can either attract or repel and depends on the charges involved. it is a vector is is measured in Newtons, like all forces it is a long distance force
how can you tell if an electric field has a strong electric field intensity?
there is a high density of electric field lines
what would be the best way to represent the charge distribution on a metal sphere when a positively charged plastic tube is placed nearby?
there is a positively charged plastic tube next to a sphere, the electrons move towards the tube and the protons repel from the tube.
a neutral metal sphere is touched by a negatively charged metal rod. as a result, the sphere will be ____ and the metal rod will be ____.
they are both negatively charged
where would you expect an electrical field vector have the greatest strength?
when it is closer to the charged object
do the equations
yeppers
