Quick questions on Capacitors - AP Physics C E&M Unit 10

4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What is parallel plate?

Show answer

A pillbox gives a uniform field

E = \dfrac{\sigma}{\varepsilon_0} = \dfrac{Q}{\varepsilon_0 A}

between the plates. The potential difference is

V = Ed = \dfrac{Qd}{\varepsilon_0 A}

, so

What is cylindrical?

Show answer

A coaxial Gaussian cylinder gives

E = \dfrac{Q}{2\pi\varepsilon_0 L r}

; integrating from

a

b

gives

V = \dfrac{Q}{2\pi\varepsilon_0 L}\ln\dfrac{b}{a}

, so

C = \dfrac{2\pi\varepsilon_0 L}{\ln(b/a)}

What is q1?

Show answer

Two capacitors,

3\,\mu\text{F}

and

6\,\mu\text{F}

, are in series. Find the equivalent capacitance. [2 points]

What is q2?

Show answer

5\,\mu\text{F}

capacitor is charged to

20

V. Find the stored energy. [2 points]

Have a question we have not covered?

This dot-point answer is short enough that we have not extracted many short questions yet. Read the full dot-point answer or ask Mo, our study assistant, in the chat for follow ups.

All Physics C: Electricity and MagnetismQ&A pages