Physics circuits

Which of the following statements are true?

-An ammeter is used to measure current. -A voltmeter must be placed in parallel with a resistor to measure the voltage across the resistor. -A voltmeter is used to measure voltage.

Which of the following statements are true?

-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 force must be maintained on the mobile charges.

Which of the following will increase the resistance of a wire?

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

Which of the following statements are true?

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

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

-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. -The equivalent resistance of the combination of resistors is less than the resistance of any one of the three resistors.

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

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

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.

A constant voltage is applied across a circuit. If the resistance in the circuit is doubled, what is the effect on the power dissipated by the circuit?

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

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.

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

-The power supplied by the source increases.

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

-Wire A has twice the resistance of wire B. -Wire A and wire B have the same resistivity.

At the same temperature, two wires made of pure copper have different resistances. The same voltage is applied at the ends of each wire. The wires may differ in...

-length. -cross-sectional area. -amount of electric current passing through them.

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

The current is doubled.

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

The resistance increases as temperature increases.

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.