Lesson test: Capacitors, storing charge in a field

1.[1p]
The charge stored on a capacitor is

proportional to the voltage across it, $Q = C V$

Correct

proportional to the current through it

The answer is: proportional to the voltage across it, $Q = CV$

independent of voltage

The answer is: proportional to the voltage across it, $Q = CV$

equal to its capacitance alone

The answer is: proportional to the voltage across it, $Q = CV$

3.[2p]
The energy stored in a capacitor is $\frac{1}{2} C V^{2}$ , with the factor of a half because

the voltage climbed from zero as the charge accumulated, so the average was half the final value

Correct

half the charge leaks away

The answer is: the voltage climbed from zero as the charge accumulated, so the average was half the final value

the capacitor is only half full

The answer is: the voltage climbed from zero as the charge accumulated, so the average was half the final value

the field cancels half the energy

The answer is: the voltage climbed from zero as the charge accumulated, so the average was half the final value

4.[3p]
A 470 microfarad capacitor is charged to 16 V. How much energy does it store, in joules? Give three decimal places.

CorrectNot quite: 0.060

5.[2p]
A capacitor blocks steady direct current but passes a changing signal because

no charge crosses the gap, but a changing voltage forces charge on and off the plates, which is a current

Correct

the dielectric conducts only alternating current

The answer is: no charge crosses the gap, but a changing voltage forces charge on and off the plates, which is a current

steady current is too small to measure

The answer is: no charge crosses the gap, but a changing voltage forces charge on and off the plates, which is a current

the plates touch when the voltage is steady

The answer is: no charge crosses the gap, but a changing voltage forces charge on and off the plates, which is a current

6.[2p]
The current into a capacitor is $I = C d V / d t$ , so it is largest when

the voltage across it is changing fastest

Correct

the voltage is steady

The answer is: the voltage across it is changing fastest

the capacitor is fully charged

The answer is: the voltage across it is changing fastest

the resistance is highest

The answer is: the voltage across it is changing fastest

7.[1p]
A capacitor stores its energy in the electric field in the gap between its plates.

True

Correct

False

The answer is: True

Sign in

Capacitors, storing charge in a field

1.[1p]
The charge stored on a capacitor is

2.[2p]
A 10 microfarad capacitor is charged to 5 V. How much charge does it hold, in microcoulombs?

3.[2p]
The energy stored in a capacitor is $\frac{1}{2} C V^{2}$ , with the factor of a half because

4.[3p]
A 470 microfarad capacitor is charged to 16 V. How much energy does it store, in joules? Give three decimal places.

5.[2p]
A capacitor blocks steady direct current but passes a changing signal because

6.[2p]
The current into a capacitor is $I = C d V / d t$ , so it is largest when

7.[1p]
A capacitor stores its energy in the electric field in the gap between its plates.

1.[1p] The charge stored on a capacitor is

2.[2p] A 10 microfarad capacitor is charged to 5 V. How much charge does it hold, in microcoulombs?

3.[2p] The energy stored in a capacitor is 12CV2, with the factor of a half because

4.[3p] A 470 microfarad capacitor is charged to 16 V. How much energy does it store, in joules? Give three decimal places.

5.[2p] A capacitor blocks steady direct current but passes a changing signal because

6.[2p] The current into a capacitor is I=CdV/dt, so it is largest when

7.[1p] A capacitor stores its energy in the electric field in the gap between its plates.

1.[1p]
The charge stored on a capacitor is

2.[2p]
A 10 microfarad capacitor is charged to 5 V. How much charge does it hold, in microcoulombs?

3.[2p]
The energy stored in a capacitor is $\frac{1}{2} C V^{2}$ , with the factor of a half because

4.[3p]
A 470 microfarad capacitor is charged to 16 V. How much energy does it store, in joules? Give three decimal places.

5.[2p]
A capacitor blocks steady direct current but passes a changing signal because

6.[2p]
The current into a capacitor is $I = C d V / d t$ , so it is largest when

7.[1p]
A capacitor stores its energy in the electric field in the gap between its plates.