Electrical Charge, Force, Electric Fields
The electric force on object A by object B is F. If the charge of object B were only half as large as it is, but everything else was kept the same, what would be the new electric force on object B by object A?
(1/2)F
The electric force on object B by object A is F. If the distance between the objects were tripled, but everything else was kept the same, what would be the new electric force on object B by object A?
(1/9)F
Which is the best definition of an electric dipole?
An electric dipole is an arrangement of electric charge with two equal but opposite amounts of charge separated by some fixed distance.
How do you calculate the electric force by object A exerted on object A (itself)?
An object never experiences an electric force due to itself.
Oxygen is the element that has 8 protons in its nucleus. If you start out with a neutral oxygen atom and it then loses 2 electrons, what is a good way to describe the resulting object?
An oxygen ion with a charge of +2e
An object with a charge of +4 μC is very close to an object with a charge of -1 μC, each one fixed in place. Which of the following is the best expression for the magnitude of the electric field we would find at a distance vector r far away from the pair of objects?
E = (1/ (4 *pi *epsilon naught )) (+3 microcoulombs) / r^2)
Which of the following is true about electric field lines due to static charge distributions?
Electric field lines are directed away from positively charged objects and toward negatively charged objects.
Which of the following is true about electric field lines due to static charge distributions?
Electric field lines cannot cross.
Which of the following is true about electric field lines due to static charge distributions?
Electric field lines will be more closely spaced from each other in regions where the electric field is stronger.
Suppose object A is electrically charged and is experiencing forces from three other charged objects. How should the total effects of those three objects be combined in order to find the total electric force?
Electric force vectors are calculated for object A and each of the other three objects. These three force vectors are then added using vector addition to obtain the total electric force.
Suppose an object starts out electrically neutral. Through some process, 11 electrons are removed from the object. What is the electric charge of the object afterward?
It has the same net charge as 11 protons.
Objects A and B are electrically repelled from each other. Can we tell what sign the charge of object A is?
No, we cannot tell.
Consider a point with a large electric field. Are there differences in how positively and negatively charged objects are affected by this electric field?
Positively and negatively charged objects both experience equal magnitude forces due to the electric field, but in opposite directions.
Consider a conductor at rest in a static electric field. Which statement is true about how the conductor interacts with the electric field?
The electric field inside the conductor is exactly zero.
Consider a conductor at rest in a static electric field. Which statement is true about how the conductor interacts with the electric field?
The electric field is perpendicular to the surface of the conductor at all points along its surface.
If a composite object is positively charged, that means it _______.
must be either made entirely from positively charged objects or made from objects that have more total positive charge than negative charge
Consider an electric dipole, composed of charges +q and -q separated by distance d, that is viewed from a large distance (large compared to d). What do we expect about the electric field due to the dipole viewed from this distance?
The electric field is significantly weaker than the electric field due to a single point charge q viewed from the same distance.
Suppose object A is experiencing an electric field with a magnitude of E at its location. If the charge on object A is doubled, what happens to the electric field it is experiencing?
The electric field that object A experiences is unchanged.
Can there be a non-zero electric field at a point in space where no charged object is present? Can there be an electric field equal to zero at a point where a charged object is present?
Yes to both. Therefore, the field can have any value (zero or non-zero) totally independent of what object is placed there.
Electric field and electric force ______.
are related quantities, but not the same thing
Two objects, each with a charge of +1 nC, are sitting alone in space. If we measure the magnitude of the electric field at a location given by vector r, which is equidistant from both objects, what result would we get?
between E=0 and E=(1/4*pi*epsilon naught) (2nC/r^2)
If a composite object is electrically neutral, that means it _______.
can be made from objects that each have zero electrical charge, or made from charged objects with equal amounts of total positive and negative charge
One similarity between protons and electrons is ______
protons and electrons have the same amount of charge, but protons have positive charge, while electrons have negative charge
