ch 19

Question 1

Capacitance

Answer 1

C is the ratio of charge Q to potential V for a conductor.

Question 2

dielectric

Answer 2

The insulating material placed between the plates of a capacitor to increase its capacitance

Question 3

electrolytic capacitor

Answer 3

Type of capacitor where the dielectric is deposited by an electrochemical reaction. These capacitors must be connected with the correct polarity for their plates, or they will be damaged

Question 4

relationship between capacitance and area and distance

Answer 4

The capacitance C is directly proportional to the area A of the plates, and inversely proportional to the distance d between them. C = ε0εrA/d e permittivity of free space ε0.relative permittivity εr

Question 5

relative permittivity εr

Answer 5

the capacitance of a parallel-plate capacitor with the dielectric between the plates divided by the capacitance of
the same capacitor with a vacuum between the plates

Question 6

how energy is stored in a capacitor

Answer 6

When charging a capacitor, work is done by the battery to move charge on to the capacitor, separating positive and negative charges. Energy is transferred from the power supply and is stored as electric potential energy in the capacitor

Question 7

the work done to charge the
capacitor (and therefore, the energy transferred to the capacitor)

Answer 7

W (and Ep) = VQ

Question 8

The energy transferred from the battery when a capacitor is charged

Answer 8

is given by the area under the graph line when charge (x-axis) is plotted against potential
difference (y-axis) E
p = 1/2QV

Question 9

exponential decay curves

Answer 9

x = x0e^–kt (and x0 is the value of x at time t = 0)

Question 10

discharge of a capacitor of capacitance C through a resistor of
resistance R is of the for

Answer 10

Q = Q0e^–t/CR