Physics II Ch. 19

In order to maintain a stead flow of current in a conductor, a stead force must ___________.

be maintained on the mobile charges.

A material that obeys Ohm's Law reasonably well is _______.

called an ohmic conductor or a linear conductor.

The resistance of a conductor is proportional to the _______.

resistivity of the material of which the conductor is composed.

Always true for series circuits:

-Adding a bulb makes the other bulbs dimmer. -Removing a bulb stops the current flow throughout the circuit. -The same current flows through each bulb in the circuit.

Consider three resistors with unequal resistances connected in series to a battery. Which of the following statements are true?

-The current flowing through each of the resistors is the same and is equal to the current supplied by the battery. -The algebraic sum of the voltages across the three resistors in equal to the voltage supplied by the battery -The equivalent resistance of the combination of resistors is greater than the resistance of any one of the three resistors

Consider three resistors with unequal resistances connected in parallel to a battery. Which of the following statements are true?

-The equivalent resistance of the combination of resistors is less than the resistance of any one of the three resistors -The algebraic sum of the currents flowing through each of the three resistors is equal to the current supplied by the battery -The voltage across each of the resistors is the same and is equal in magnitude to the voltage of the battery

Always true about simple parallel circuits:

-There is the same voltage across each bulb in the circuit. -Removing a bulb does not stop the current flow throughout the circuit.

The brightness of identical bulbs varies depending on whether or not they are connected in series or parallel. Rank brightest to dimmest. A is in series, B and C are parallel after A.

A > B=C

Consider two copper wires with the same cross-sectional area. Wire A is twice as long as wire B. How do the resistivity and resistances of the two wires compare?

A has twice the resistance as B. A and B have same resistivity.

Not true about series or parallel circuits:

Adding a bulb makes the other bulbs brighter.

For a series circuit, what will be true if a switch is closed before 3 light bulbs?

All three bulbs will remain the same brightness.

Which of the following would double the amount of current flowing through a piece of metal wire?

Double the voltage across it.

Rank most current (least resistance) to least current (most resistance).

Wire of Length and 2area > Length and Area > 2Length and Area

If the resistivity of copper is less than that of gold at room temperature, which of the following statements must be true?

Electrons in gold are more likley to be scattered than electrons in copper at room temperature when they are accelerated by teh same electric field.

What is the direction of the magnetic force on this wire due to the magnet?

Into the paper

What happens to the current supplied by the battery when you add an identical bulb in parallel to the original bulb

The current doubles.

If the voltage across a circuit of constant resistance is doubled, how is the current in the circuit affected?

The current is doubled. V = IR

Is a series circuit, resistor A has three times the resistance of resistor B. Therefore, ______:

The potential difference across A is three times the potential difference across B.

A circuit maintains a constant resistance. If the current in the circuit is doubled, what is the effect on the power dissipated by the circuit?

The power dissipated is quadrupled

As additional resistors are connected in series to a constant voltage source, how is the power supplied by the source affected?

The power supplied by the source decreases.

What is the effect of the magnetic field on the protons?

The protons are accelerated upward.

In a series circuit with two identical bulbs, what happens to the remaining bulb when one is replaced with a wire?

The remaining bulb gets brighter.

What happens to the resistance of most common metals as the temperature of the metal increases?

The resistance increases as temperature increases.

How do the resistances of two conducting wires compare if they have the same length, but one is twice the radius of the other?

The thicker wire has one-fourth the resistance of the thinner wire.

If the resistance in a circuit connected to a constant current is halved, how is the voltage in the circuit affected?

The voltage is reduced by a factor of 2. V = IR

When you close the switch, bulbs B1 and B2 will be ______:

just as bright as before.

Good conduction of electricity have ______.

larger conductivity values than insulators.

Current is the total amount of charge that ____________.

passes through a conductor's full cross section at any point per unit of time.

Three identical lightbulbs, AA, BB, and CC, are connected in the circuit. When the switch is closed ______

the brightness of A and B increases, but C goes out.