Pre-Class 5

A  The power dissipated is doubled.

B  The power dissipated is reduced by a factor of 2.

C  The power dissipated is quadrupled.

D  The power dissipated remains constant.

E  The power dissipated is reduced by a factor of 4.

A  The current is quadrupled.

B  The current is reduced by a factor of 2.

C  The current is doubled.

D  The current remains constant.

E  The current is reduced by a factor of 4.

A  Semiconductors have resistivity values that are larger than those of insulators. The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed. Good conductors of electricity have larger conductivity values than insulators.

B  Semiconductors have resistivity values that are larger than those of insulators. The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed. A material that obeys Ohm’s law reasonably well is called an ohmic conductor or a linear conductor.

C  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. Good conductors of electricity have larger conductivity values than insulators.

D  Semiconductors have resistivity values that are larger than those of insulators. The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed.

A  Increasing the cross-sectional area of the wire will increase the resistance of the wire. Increasing the length of the wire will increase the resistance of the wire.. Decreasing the resistivity of the material the wire is composed of will increase the resistance of the wire.

B  Increasing the resistivity of the material the wire is composed of will increase the resistance of the wire. Increasing the length of the wire will increase the resistance of the wire. Decreasing the cross-sectional area of the wire will increase the resistance of the wire.

C  Increasing the cross-sectional area of the wire will increase the resistance of the wire. Decreasing the length of the wire will increase the resistance of the wire. Decreasing the cross-sectional area of the wire will increase the resistance of the wire.

D  Increasing the cross-sectional area of the wire will increase the resistance of the wire. Decreasing the length of the wire will increase the resistance of the wire. Decreasing the resistivity of the material the wire is composed of will increase the resistance of the wire.

A  When an electric field is applied to a conductor, the free electrons move only in the direction opposite the applied electric field. By convention, the direction of a current is taken to be the direction of flow for negative charges.

B  In a circuit, current is delivered by the positive terminal of a battery, and it is used up by the time it returns to the negative terminal of the battery. By convention, the direction of a current is taken to be the direction of flow for negative charges.

C  In a circuit, current is delivered by the positive terminal of a battery, and it is used up by the time it returns to the negative terminal of the battery. When an electric field is applied to a conductor, the free electrons move only in the direction opposite the applied electric field.

D  Current is the total amount of charge that passes through a conductor’s full cross section at any point per unit of time. In order to maintain a steady flow of current in a conductor, a steady, external force must be maintained on the mobile charges.

A  The potential difference between the terminals of a battery, when no current flows to an external circuit, isreferred to as the terminal voltage. A battery is a device that produces electricity by transforming chemical energy into electrical energy.

B  A battery does work on electric charges to bring them to a position of higher electric potential energy so that they
can flow through a circuit to a lower potential energy. The internal resistance of a battery decreases with decreasing temperature.

C  A battery is a device that produces electricity by transforming chemical energy into electrical energy. A battery does work on electric charges to bring them to a position of higher electric potential energy so that they can flow through a circuit to a lower potential energy

D  The potential difference between the terminals of a battery, when no current flows to an external circuit, isreferred to as the terminal voltage. The internal resistance of a battery decreases with decreasing temperature.