Physics Conceptual questions

Fig. 24-1 shows 3 capacitors, of equal capacitance C, connected to a battery of voltage V. What is the equivalent capacitance of this combination?

2C/3

A 1 pF capacitor is connected in parallel with a 2 pF capacitor, the parallel combination then being connected in series with a 3 pF capacitor. The resulting combination is then connected across a battery. Which capacitor has the greatest charge?Which capacitor has the greatest voltage?

3pF; all capacitors have the same charge

A 1 mF, a 2 mF, and a 3 mF capacitor are connected in series, the combination being connected across a 9 volt battery. Which capacitor has the greatest chargeWhich capacitor has the greatest voltage?

All capacitors have the same charge.; 1mF

Fig. 24-2 shows three capacitors connected to a battery. The capacitances are such that C1 = 2C2 and C1 = 3C3. Which capacitor stores the smallest amount of charge?

All three capacitors store the same amount of charge.

Three capacitors C1, C2, and C3 are connected to a battery as shown in Fig. 24-3. The three capacitors have equal capacitances. Which capacitor stores the most potential energy?

C1

The change in electric potential energy, Ub - Ua, is the work done on a charge by the electric force as it moves from point a to point b.

False

When a proton moves in a direction of the electric field, its potential increases but its potential energy decreases.

False

Three identical capacitors are connected in parallel to a battery. If a total charge of Q flows from the battery, how much charge does each capacitor carry?

Q/3

The voltage applied across a given parallel-plate capacitor is doubled. How is the energy stored in the capacitor affected?

The energy stored in the capacitor quadruples its original value.

A dielectric is inserted between the plates of an isolated parallel-plate capacitor that carries a charge Q. What happens to the potential energy stored in the capacitor?

The potential energy of the capacitor decreases.

The plates of a parallel-plate capacitor are maintained with a constant voltage by a battery as they are pulled apart. How is the strength of the electric field affected during this process?

The strength of the electric field decreases during this process.

Consider two copper wires of the same length. One has twice the cross-sectional area of the other. How do the resistances of these two wires compare?

The thicker wire has half the resistance of the shorter wire.

Fig. 23-1 shows equipotentials surrounding a pair of charges QA and QB. The value of the potential half-way between the charges is indicated. Which of the statements below applies to the charges?

The two charges have opposite signs and equal magnitudes.

The energy acquired by a particle carrying a charge equal to that on the electron as a result of moving through a potential difference of one volt is referred to as

an electron-volt.

A capacitor consists of a set of two parallel plates of area A separated by a distance d. This capacitor is connected to a battery that maintains a constant potential difference between the plates. If the separation between the plates is doubled, the magnitude of the electrical energy stored on the capacitor will

be cut in half.

A dielectric material such as paper is placed between the plates of a capacitor holding a fixed charge. What happens to the electric field between the plates?

becomes weaker

The work done in moving a positive charge against an electric field does not depend on the path chosen in moving the charge in that field. Based on the statement, what kind of force field is the electrostatic field?

conservative

The plates of a parallel-plate capacitor are maintained with constant voltage by a battery as they are pulled apart. During this process, the amount of charge on the plates must

decrease

A capacitor consists of a set of two parallel plates of area A separated by a distance d. The capacitor plates carry charges +Q and -Q. If the separation between the plates is doubled, the electrical energy stored in the capacitor will

double

A capacitor consists of a set of two parallel plates of area A separated by a distance d. The capacitor plates cary charges +Q and -Q. If the separation between the plates is doubled, the potential difference between the plates will

double

Electric dipoles always consist of two charges that are

equal in magnitude; opposite in sign.

A battery creates net electric charge

false

A battery is responsible for supplying a constant current to a circuit.

false

As more and more capacitors are connected in series, the equivalent capacitance of the combination increases.

false

Current in a metal wire is inversely proportional to the potential difference applied to its two ends.

false

If a fuse repeatedly blows, it should be replaced by a fuse of one step higher rating.

false

The fatter a given length of wire, the higher its resistance.

false

The resistance of most metals generally decreases with temperature.

false

The resistivity of the material of a wire is inversely proportional to the resistance of the wire.

false

Current flows through a resistor

from high potential to low potential

A negative charge, if free, tries to move

from low potential to high potential

The resistivity of most common metals

increases as the temperature increases.

The potential of a uniformly charged sphere is lowest at

infinity

If the voltage applied to a parallel-plate capacitor is doubled, the electric field between the plates

is doubled

If the voltage between the plates of a parallel-plate capacitor is doubled, the charge on the capacitor

is doubled

The plates of a parallel-plate capacitor are maintained with constant voltage by a battery as they are pulled apart. What happens to the strength of the electric field during this process?

it decreases

An advantage of a circuit breaker over a fuse is

it is easier to re-enable the circuit.

For a proton moving in the direction of the electric field

its potential energy decreases and its electrical potential decreases

Outlets on a household circuit are arranged in

parallel

An equipotential surface must be

perpendicular to the electric field at every point

Fig. 25-1 shows an electric charge of unknown polarity moving inside a conducting wire. If the electric field in the conductor is oriented as shown, what is the sign of the charge?

positive

If the voltage on a capacitor is doubled, then the energy stored by the capacitor

quadruples

If the voltage between the plates of a parallel-plate capacitor is doubled, the capacitance of the capacitor

remains the same

A 1200-W toaster draws more current than a 1000-W toaster.

true

A lightbulb cannot absorb charge.

true

All points on the perpendicular bisector of the line joining two equal but opposite charges have a potential of zero.

true

As more and more capacitors are connected in parallel, the equivalent capacitance of the combination increases.

true

Capacitors in series share the same charge and capacitors in parallel share the same voltage.

true

Conventional current is the flow of positive charge from higher to lower potential.

true

Equipotential lines and electric field lines meet perpendicular to one another.

true

Every point on an equipotential surface is at the same potential.

true

The current in a circuit flows in the opposite direction to the direction in which the electrons move.

true

The direction of an electric field is from higher to lower potential.

true

The energy stored in a capacitor will be equal to the work done to charge it.

true

The longer a given diameter of wire, the higher its resistance.

true

The potential outside a uniformly charged sphere is the same as if all the charge were concentrated at its center.

true