Physics Chapter 21: Electric Current and Electric Circuits

Current in a circuit is best described as _____.

• the rate at which electrons move per volt

• the rate at which charges flow over a given time

• the rate at which resistance changes over time

• the rate at which volts change per charge in Coulombs

In a circuit, what does voltage do?

• measure the current flowing through the circuit

• push/cause electrons to move

• turn on or off electrical switches

• limit the amount of energy allowed

In alternating-current circuits, the current flows in _____ direction.

• periodically reverse/opposite

• East to West

• one constant

• counter-clockwise

In circuits, as a wire is heated, its resistance tends to _____.

• decrease

• increase

• remain the same

When the electric charge flows from one place to another, we say that it forms _____.

• a resistance

• a potential difference

• a total charge

• an electric current

Refer to the circuit diagram. The section labeled 330 ohms refers to the circuit's _____.

• voltage

• electric field strength

• current

• resistance

The applied voltage equals the product of the _________ and wire's __________.

• current and resistance

• size and length

• charge and temperature

• force and material

When a potential difference of 18 V is applied to a given wire, the wire conducts 0.35 A of current. What is the resistance of the wire? 

• 0.019 ohms

• 6.3 ohms

• 19 ohms

• 51 ohms

What are 2 basic things required to form a circuit?

• (1) made of highly conductive material (2) a flowing charge

• (1) positive and negative terminals (2) it must be a closed loop

• (1) energy supply (2) it must be a closed loop

• (1) energy supply (2) a flowing charge

The direction of the current in a circuit is the direction in which a _____ test charge would move. The actual charge, the movement of electrons, travels in _____ direction. 

• negative, the same

• negative, the opposite

• positive, the opposite

• positive, the same