PHYSICS 202 - Module 21 Electric Charge, Force, Electric Fields

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? A. Start fraction 1 divided by 9 end fraction times F B. 9F C. 1/3F D. 3F E. F

C. 1/3F

How do you calculate the electric force by object A exerted on object A (itself)? A. Use Coulomb's law with just one charge, q sub A, instead of two charges multiplied together. B. Use Coulomb's law with r is equal to 0. C. An object never experiences an electric force due to itself. D. The force on object A is calculated by using the field caused by object A times the charge of object A, F is equal to q sub a times E sub a.

C. An object never experiences an electric force due to itself.

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? A. Yes to both. B. No, there cannot be a non-zero field without an object at that point, but there can be an electric field equal to zero at a point where a charged object is present. C. No to both. D. Yes, there can be a non-zero field without an object at that point, but there cannot be an electric field equal to zero at a point where a charged object is present.

Yes to both.

Which of the following is true about electric field lines due to static charge distributions? A. Electric field lines are directed away from positively charged objects and toward negatively charged objects. B. Electric field lines must loop back and connect to themselves (forming a closed loop). C. Electric field lines will cross wherever the electric field is zero. D. Electric field lines will be more closely spaced from each other in regions where the electric field is weaker.

A. 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? A. Electric field lines cannot be curved. B. Electric field lines cannot cross. C. Electric field lines must loop back and connect to themselves (forming a closed loop). D. Electric field lines start on a negatively charged object and end on a positively charged object.

B. Electric field lines cannot cross.

Objects A and B are electrically repelled from each other. Can we tell what sign the charge of object A is? A. The stated situation isnât possible. B. No, we cannot tell. C. Yes, it must be positive (+). D. Yes, it must be negative (-).

B. No, we cannot tell.

Consider a conductor at rest in a static electric field. Which statement is true about how the conductor interacts with the electric field? A. The electric field inside the conductor has a constant non-zero magnitude throughout the conductor. B. The electric field is perpendicular to the surface of the conductor at all points along its surface. C. The electric field lines pass through the conductor unaffected by its presence (as if it weren't there). D. Any net charge on the conductor is distributed evenly throughout the volume of the conductor.

B. The electric field is perpendicular to the surface of the conductor at all points along its surface.

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? A. The electric field could be weaker or stronger than a single point charge q viewed from the same distance. B. The electric field is significantly weaker than the electric field due to a single point charge q viewed from the same distance. C. The electric field is significantly stronger than a single point charge q viewed from the same distance. D. The electric field will be exactly zero.

B. The electric field is significantly weaker than the electric field due to a single point charge q viewed from the same distance.

Electric field and electric force ______. A.are not the same because electric field refers to the effects of multiple electric forces B. are related quantities, but not the same thing C. are synonyms referring to the same thing D. are unrelated to each other

B. are related quantities, but not the same thing

Which is the best definition of an electric dipole? A. An electric dipole is an arrangement of two opposite charges of equal or unequal amounts separated by some fixed distance. B. An electric dipole is an arrangement of electric charge with two equal but opposite amounts of charge separated that are moving toward each other due to their mutual attraction. C. An electric dipole is an arrangement of electric charge with two equal but opposite amounts of charge separated by some fixed distance. D. An electric dipole is an arrangement of two identical electric charges separated by some fixed distance.

C. An electric dipole is an arrangement of electric charge with two equal but opposite amounts of charge separated by some fixed distance.

Consider a conductor at rest in a static electric field. Which statement is true about how the conductor interacts with the electric field? A. The electric field lines pass through the conductor unaffected by its presence (as if it weren't there). B. The electric field is parallel to the surface of the conductor at all points along its surface. C. Any net charge on the conductor resides on the surface of the conductor. D. The electric field inside the conductor has a constant non-zero magnitude throughout the conductor.

C. Any net charge on the conductor resides on the surface of the conductor.

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? A. It has the same net charge as 11 electrons. B. The stated situation isn't possible. C. It has the same net charge as 11 protons. D. It has a net charge somewhere between the charge of 11 electrons and 11 protons, but we can't tell exactly how much.

C. It has the same net charge as 11 protons.

Consider a point with a large electric field. Are there differences in how positively and negatively charged objects are affected by this electric field? A. Neither positively nor negatively charged objects experience a force due to the electric field. B. Negatively charged objects experience a larger magnitude force due to the electric field than positively charged objects. C. Positively and negatively charged objects both experience equal magnitude forces due to the electric field, but in opposite directions. D. Positively charged objects experience a larger magnitude force due to the electric field than negatively charged objects.

C. Positively and negatively charged objects both experience equal magnitude forces due to the electric field, but in opposite directions.

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? A. The electric field that object A experiences is halved. B. The electric field that object A experiences is quadrupled. C. The electric field that object A experiences is unchanged. D. The electric field that object A experiences doubles.

C. The electric field that object A experiences is unchanged.

If a composite object is electrically neutral, that means it _______. A. can only be made from objects that don't have "electrical charge" as a property B. can only be made from objects that each have zero electrical charge C. 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 D. can only be made from charged objects with equal amounts of total positive and negative charge

C. 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

The electric force between objects A and B is F. If the charge of object A were twice as large as it is, but everything else was kept the same, what would be the new electric force between objects A and B? A. F B. 3F C. 4F D. 2F

D. 2F

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? A. E is equal to start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction positive 4 microcoulombs times negative 1 microcoulomb over r squared end fraction B. E is equal to start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction 4 microcoulombs over r squared end fraction plus start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction 1 microcoulomb over r squared end fraction C. E is equal to start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction negative 4 microcoulombs over r squared end fraction D. E is equal to start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction positive 3 microcoulombs over r squared end fraction

D. E is equal to start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction positive 3 microcoulombs over r squared end fraction

Which of the following is true about electric field lines due to static charge distributions? A. Electric field lines cannot be curved. B. Electric field lines must loop back and connect to themselves (forming a closed loop). C. Electric field lines will cross wherever the electric field is zero. D. Electric field lines will be more closely spaced from each other in regions where the electric field is stronger.

D. 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? A. The magnitudes of the electric force are calculated for object A and each of the other three objects. These three magnitudes are then added to obtain the total electric force. B. The charges of the three other charged objects are combined into one net charge which is then used to calculate the total electric force on object A. C. Electric force vectors are calculated for each pair of objects (six forces in total). These six force vectors are then added using vector addition to obtain the total electric force. D. 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.

D. 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.

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? A. 1/4F B. 1/2F C. 2F D. F

1/2F

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? A. 3F B. 1/3F C. F D. 9F E. 1/9F

1/9F

Consider a conductor at rest in a static electric field. Which statement is true about how the conductor interacts with the electric field? A. The electric field inside the conductor is exactly zero. B. Any net charge on the conductor is distributed evenly throughout the volume of the conductor. C. The electric field is parallel to the surface of the conductor at all points along its surface. D. The electric field lines pass through the conductor unaffected by its presence (as if it werenât there)

A. The electric field inside the conductor is exactly zero.

If a composite object is positively charged, that means it _______. A. must be either made entirely from positively charged objects or made from objects that have more total positive charge than negative charge B. must be made from objects that have more total positive charge than negative charge C. must be made from a larger number of positively charged objects than negatively charged objects D. must be made entirely from positively charged objects

A. must be either made entirely from positively charged objects or made from objects that have more total positive charge than negative charge

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 is equal to 0 and E is equal to start fraction 1 over 4 times pi times epsilon naught end fraction times start fraction 2 nanocoulombs over r squared end fraction

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? A. A carbon ion with a charge of +2e B. A carbon atom C. An oxygen ion with a charge of -2e D. An oxygen ion with a charge of +2e E. A carbon ion with a charge of -2e

An oxygen ion with a charge of +2e

One similarity between protons and electrons is ______. A. protons and electrons have the same amount of charge, but protons have positive charge, while electrons have negative charge B. protons and electrons have the same amount of charge, but protons have negative charge, while electrons have positive charge C. protons and electrons have the exact same mass D. protons and electrons have the exact same chargeA

protons and electrons have the same amount of charge, but protons have positive charge, while electrons have negative charge