Capacitance and Capacitors

Increasing the separation of the two charged parallel plates of a capacitor, which are disconnected from a battery, will produce what effect on the capacitor?

• increase charge

• decrease charge

• increase capacitance

• decrease capacitance

A parallel-plate capacitor has dimensions 4.0 cm x 5.0 cm. The plates are separated by a 1.0 mm thickness of paper (dielectric constant k = 3.7). What is the charge that can be stored on this capacitor, when connected to a 1.5 V battery? (Ɛ₀ = 8.85 x 10^-12 C²/Nm²)

• 20 x 10^-12 C

• 4.8 x 10^-12 C

• 4.8 x 10^-11 C

• 9.8 x 10^-11 C

Tags

NGSS.HS-PS2-4

Very large capacitors have been considered as a means for storing electrical energy. If we constructed a very large parallel-plate capacitor of plate area 1.0 m² using paper (k = 3.7) of thickness 1.0 mm as a dielectric, how much electrical energy would it store at a plate voltage of 5 000 V?

• 0.41 J

• 90 J

• 9 000 J

• 45 000 J

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

• Area = energy

• Area = capacitance

• Area = resistance

• Gradient = current

The capacitance of a parallel-plate capacitor can be increased by: 

• increasing the charge 

• decreasing the charge 

• increasing the plate separation

• decreasing the plate separation 

A capacitor is charged by a constant current of 4.0 mA for 0.80 s. If the potential difference across the capacitor is 320 V, what is the capacitance of the capacitor?

A parallel-plate capacitor of cross-sectional area A is connected across a battery of potential difference V. A dielectric is then inserted into the capacitor. If the relative permittivity of the dielectric is 2.5 and the distance of separation between the plates is 0.050 mm, calculate the ratio of charge on the capacitor without the dielectric to the charge on the capacitor with dielectric.

• 2:5

• 5:2

• 1:4

• 1:2

• 60 V

• 40 V

• 20 V

• 10 V

A capacitor is connected in series with a light bulb and a voltage supply as shown in the diagram. If a dielectric is inserted between the parallel plates of the capacitor, which statement is not true about the capacitor?

• The potential difference across the capacitor remains constant.

• The electric field strength between the plates increases at the moment the dielectric is inserted.

• The charge on the capacitor increases.

• The capacitance of the capacitor increases.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

Nine capacitors are arranged in a circuit as shown in the diagram. Which section of the circuit provides the lowest capacitance?

• PQ

• PR

• ST

• TU