Lesson test: Inductors and the magnetic field

1.[1p]
An inductor stores energy in

the magnetic field set up by the current in its coil

Correct

the electric field between two plates

The answer is: the magnetic field set up by the current in its coil

the charge on its surface

The answer is: the magnetic field set up by the current in its coil

the resistance of its wire

The answer is: the magnetic field set up by the current in its coil

2.[2p]
Lenz's law says the voltage induced in an inductor

always opposes the change in current that caused it

Correct

always adds to the change in current

The answer is: always opposes the change in current that caused it

is zero for any changing current

The answer is: always opposes the change in current that caused it

points in a random direction

The answer is: always opposes the change in current that caused it

3.[2p]
The current through a 2 millihenry inductor is increasing at 500 amperes per second. What voltage, in volts, appears across it?

CorrectNot quite: 1

4.[2p]
The relation $V = L d I / d t$ is the mirror of the capacitor's $I = C d V / d t$ because

an inductor resists changes in current the way a capacitor resists changes in voltage

Correct

both components store charge

The answer is: an inductor resists changes in current the way a capacitor resists changes in voltage

both dissipate energy as heat

The answer is: an inductor resists changes in current the way a capacitor resists changes in voltage

inductance equals capacitance

The answer is: an inductor resists changes in current the way a capacitor resists changes in voltage

5.[3p]
How much energy, in joules, is stored in a 10 millihenry inductor carrying 3 A? Use $E = \frac{1}{2} L I^{2}$ .

CorrectNot quite: 0.045

6.[2p]
To steady direct current an inductor behaves like

a plain wire, because a steady current has zero rate of change and meets no opposition

Correct

an open circuit

The answer is: a plain wire, because a steady current has zero rate of change and meets no opposition

a large resistor

The answer is: a plain wire, because a steady current has zero rate of change and meets no opposition

a capacitor

The answer is: a plain wire, because a steady current has zero rate of change and meets no opposition

7.[2p]
Opening a switch on an inductor carrying current can throw a spark, because the inductor develops a large voltage fighting to keep the current flowing.

True

Correct

False

The answer is: True

1.[1p] An inductor stores energy in

2.[2p] Lenz's law says the voltage induced in an inductor

3.[2p] The current through a 2 millihenry inductor is increasing at 500 amperes per second. What voltage, in volts, appears across it?

4.[2p] The relation V=LdI/dt is the mirror of the capacitor's I=CdV/dt because

5.[3p] How much energy, in joules, is stored in a 10 millihenry inductor carrying 3 A? Use E=12LI2.

6.[2p] To steady direct current an inductor behaves like

7.[2p] Opening a switch on an inductor carrying current can throw a spark, because the inductor develops a large voltage fighting to keep the current flowing.

1.[1p]
An inductor stores energy in

2.[2p]
Lenz's law says the voltage induced in an inductor

3.[2p]
The current through a 2 millihenry inductor is increasing at 500 amperes per second. What voltage, in volts, appears across it?

4.[2p]
The relation $V = L d I / d t$ is the mirror of the capacitor's $I = C d V / d t$ because

5.[3p]
How much energy, in joules, is stored in a 10 millihenry inductor carrying 3 A? Use $E = \frac{1}{2} L I^{2}$ .

6.[2p]
To steady direct current an inductor behaves like

7.[2p]
Opening a switch on an inductor carrying current can throw a spark, because the inductor develops a large voltage fighting to keep the current flowing.