AP Physics 1:: Electric Charge Force

What is ELECTRIC CHARGE, and what are the TWO TYPES of electric charge that exist in nature?

- **A)** Electric charge comes in THREE types (positive, negative, and neutral), rather than just two
- **B)** There is only ONE type of electric charge, with no actual distinction between positive and negative
- **C)** This concept has no actual relationship between electric charge and the existence of two distinct charge types
- **D)** Electric charge is a fundamental property of matter that gives rise to electric and magnetic forces; the two types are POSITIVE and NEGATIVE charge -- protons carry positive charge, and electrons carry negative charge

What is the fundamental RULE governing whether two charged objects ATTRACT or REPEL each other, based on their charge signs?

- **A)** All charged objects ALWAYS attract each other, regardless of whether their charges are the same sign or different signs
- **B)** Like charges ATTRACT each other, while opposite charges REPEL each other -- the reverse of the actual relationship
- **C)** LIKE charges (both positive or both negative) REPEL each other, while OPPOSITE charges (one positive, one negative) ATTRACT each other
- **D)** This concept has no actual relationship between charge signs and whether two charged objects attract or repel

What is the SI (metric) UNIT of electric charge, and approximately what is the magnitude of the charge carried by a SINGLE electron or proton (the ELEMENTARY CHARGE), in these units?

- **A)** This concept has no actual relationship between the SI unit for charge and the elementary charge of a single electron or proton
- **B)** The COULOMB (C); the elementary charge (magnitude of a single electron's or proton's charge) is approximately 1.6 x 10^-19 C -- an extremely small quantity, meaning everyday charged objects contain enormous numbers of excess or deficit electrons
- **C)** The SI unit of charge is the NEWTON, identical to the unit of force, with no distinct unit for charge
- **D)** The elementary charge is approximately 1.6 x 10^19 C (a very LARGE number), rather than 1.6 x 10^-19 C (a very small number)

What is the LAW OF CONSERVATION OF CHARGE, and what does it state about the TOTAL electric charge of an ISOLATED system during any physical process (like charging by friction or contact)?

- **A)** Conservation of charge requires that EACH INDIVIDUAL object's charge remains SEPARATELY constant, rather than the TOTAL charge of the system remaining constant
- **B)** Electric charge can be freely CREATED or DESTROYED during physical processes like friction or contact, contradicting the law of conservation of charge
- **C)** The law of conservation of charge states that the TOTAL electric charge of an isolated system remains CONSTANT -- charge can be TRANSFERRED between objects within the system (e.g., electrons moving from one object to another), but the TOTAL amount of charge is neither created nor destroyed
- **D)** This law has no actual relationship to how total charge behaves during physical processes within an isolated system

What is CHARGING BY FRICTION, and what happens at the MICROSCOPIC level (in terms of electron transfer) when two different, initially NEUTRAL materials are rubbed together?

- **A)** This concept has no actual relationship between rubbing two materials together and any resulting electron transfer or charging
- **B)** Charging by friction involves the creation of entirely NEW charge, rather than the transfer of existing electrons between the two materials
- **C)** Charging by friction transfers PROTONS (rather than electrons) between the two materials' surfaces
- **D)** When two different materials are rubbed together, ELECTRONS can be transferred from one material's surface to the other (depending on how strongly each material's atoms hold their outer electrons) -- the material that LOSES electrons becomes POSITIVELY charged, while the material that GAINS electrons becomes NEGATIVELY charged

What is CHARGING BY CONDUCTION (also called charging by CONTACT), and how does the resulting charge on a previously NEUTRAL object compare, in SIGN, to the charge on the charged object that touched it?

- **A)** Charging by conduction occurs when a charged object makes DIRECT PHYSICAL CONTACT with a neutral object, transferring SOME of its excess charge to the previously neutral object -- the neutral object ends up with the SAME SIGN of charge as the original charged object
- **B)** This concept has no actual relationship between direct contact charging and the resulting charge sign on a previously neutral object
- **C)** Charging by conduction requires the two objects to NOT actually touch each other, contradicting the definition of contact-based charging
- **D)** Charging by conduction always gives the previously neutral object the OPPOSITE sign of charge compared to the object that touched it

What is CHARGING BY INDUCTION, and how does the resulting charge on a nearby, initially NEUTRAL, GROUNDED conductor compare, in SIGN, to the charge on a NEARBY (but non-touching) charged object?

- **A)** Charging by induction occurs when a charged object is brought NEAR (but does NOT touch) a neutral conductor, causing charge REDISTRIBUTION within the conductor; if the conductor is then briefly GROUNDED (allowing excess charge to flow away) while the charged object remains nearby, the conductor ends up with the OPPOSITE sign of charge compared to the nearby charged object
- **B)** Charging by induction gives the neutral conductor the SAME sign of charge as the nearby charged object, rather than the opposite sign
- **C)** This concept has no actual relationship between induction charging and the resulting charge sign on a grounded, initially neutral conductor
- **D)** Charging by induction always requires DIRECT CONTACT between the two objects, contradicting the defining no-contact feature of induction charging

What is COULOMB'S LAW, and what is its mathematical FORMULA relating the ELECTRIC FORCE between two point charges to their charge magnitudes and the DISTANCE between them?

- **A)** Coulomb's Law states that electric force is DIRECTLY proportional to the distance between two charges, rather than inversely proportional to the square of that distance
- **B)** This law has no actual mathematical relationship between electric force, charge magnitudes, and the distance between two point charges
- **C)** Coulomb's Law states that the electric force between two point charges is F = k*q1*q2/r^2, where k is Coulomb's constant, q1 and q2 are the charge magnitudes, and r is the distance between them -- this force is DIRECTLY proportional to the product of the charges and INVERSELY proportional to the SQUARE of the distance
- **D)** Coulomb's Law states that electric force depends only on the distance between two charges, with no actual dependence on the charge magnitudes themselves