Title: Capactiors - final questions

Fill in the missing words

Q: In a capacitor, energy is stored in the form of an [...].

The [...] on a capacitor is proportional to the [...] applied across the capacitor. The [...] is the capacitance.
A: electric field; charge; voltage; proportionality factor

Capacitance

Q: Which variables determine the capacitance of a capacitor?
- the material inbetween the plates (correct)
- the distance between the plates (correct)
- the area of the plates (correct)
- the thickness of the plates
- the material of the plates

Q: In a circuit, there is only a source and a capacitor connected in series. Next, the distance between the plates of the charged capacitor connected to the electrical source is extended from d to 2d. What happens?
- The voltage remains the same. (correct)
- The voltage is halved.
- The voltage doubles.
- The charge remains the same.
- The charge doubles.
- The charge is halved. (correct)

Q: A capacitor across which a voltage of 3.1 V is applied, contains a charge of 5.3 * 10^-6 C. What is the capacitance of the capacitor?
- 1.7*10^-6 F (correct)
- 1.6*10^-5 F
- 5.8*10^5 F
- 3.4*10^-6 F

Fill in the missing words

Q: Capacitors connected in parallel are equivalent to a capacitor with a larger [...]. Capacitors connected in series on the other hand are equivalent to a capacitor with a larger [...]
A: surface area/area/surface; distance between the plates/distance between plates

Look at the circuit on the right.

Q: The capacitor with capacitance C = 10 mF is charged to 100 V. At t=0, the switch is opened. Find

     1. the energy stored by the capacitor: w = [...] J

     2. the voltage across the capacitor at t=0+, right after the switch is opened: v(0+) = [...] V
A: 50; 100

[Image: circuit]

For a more detailed explanation click onto the next slide.

The capacitor with capacitance C = 10 mF is charged to 100 V. At t=0, the switch is opened.

     1. The energy stored by the capacitor is:

     2. The voltage across the capacitor at t=0+, right after the switch is opened, is:

[Image: circuit]

[Image: energy]

[Image: voltage]