AC Circuits: Crash Course Physics #36

What is the main difference between direct current (DC) and alternating current (AC) in a circuit?

• DC current changes direction constantly, while AC current flows in one direction.

• DC current is used for lights, while AC current is used for batteries.

• DC current flows in one constant direction, while AC current constantly changes direction.

• DC current has changing voltage, while AC current has constant voltage.

In an alternating current (AC) circuit, what does "peak" refer to for current or voltage?

• The average value of the current or voltage.

• The highest or lowest value (positive or negative) of the current or voltage.

• The constant value that never changes.

• The total amount of energy in the circuit.

What is self-inductance in an AC circuit?

• When a changing current creates a magnetic field that helps the main current.

• When a changing current creates an opposing magnetic field and EMF.

• When a constant current creates a magnetic field.

• When a circuit only uses resistors.

What is an inductor designed to do in an electrical circuit?

• To store electrical charge.

• To increase the resistance of the circuit.

• To maximize self-inductance.

• To convert AC current to DC current.

In an inductor circuit, how is the time constant calculated?

• Inductance divided by Resistance

• Voltage divided by Resistance

• Current divided by Resistance

• Inductance multiplied by Resistance

If a car has a small time constant, what does that mean for its speed?

• It takes a long time to speed up.

• It takes less time to speed up.

• It cannot speed up very much.

• It only slows down quickly.

What happens to the electric current in a circuit with an inductor if the power source is suddenly turned off?

• The current stops immediately.

• The current slowly decreases over time.

• The current suddenly increases.

• The current stays the same.

In a circuit that only has a resistor, what is true about the voltage and current?

• The current happens before the voltage.

• The voltage happens before the current.

• The current and voltage happen at the same time.

• The current and voltage never happen at the same time.