You have a parallel plate capacitor (with air between its plates) which is attached to a voltage source until the capacitor is fully charged.
(a)After detaching the capcitor from the voltage source, you move the capacitor's plates farther apart; which of the following will occur (check all that apply)?
a.the capacitor's capacitance will increase
b.the capacitor's capacitance will decrease
c.the capacitor's capacitance will remain the same
d.the magnitude of the charge on each of the capacitor's plates will increase
e.the magnitude of the charge on each of the capacitor's plates will decrease
f.the magnitude of the charge on each of the capacitor's plates will remain constant
g.the potential difference across the capacitor's plates will increase
h.the potential difference across the capacitor's plates will decrease
i.the potential difference across the capacitor's plates will remain the same
j.the potential energy stored in the capacitor will increase
k.the potential energy stored in the capacitor will decrease
l.the potential energy stored in the capacitor will remain the same
m.more information is needed to be able to answer this
(b)While the capacitor is still attached to the voltage source, you move the capacitor's plates closer together; which of the following will occur (check all that apply)?
a.the capacitor's capacitance will increase
b.the capacitor's capacitance will decrease
c.the capacitor's capacitance will remain the same
d.the magnitude of the charge on each of the capacitor's plates will increase
e.the magnitude of the charge on each of the capacitor's plates will decrease
f.the magnitude of the charge on each of the capacitor's plates will remain constant
g.the potential difference across the capacitor's plates will increase
h.the potential difference across the capacitor's plates will decrease
i.the potential difference across the capacitor's plates will remain the same
j.the potential energy stored in the capacitor will increase
k.the potential energy stored in the capacitor will decrease
l.the potential energy stored in the capacitor will remain the same
m.more information is needed to be able to answer this
(a) After detaching the capacitor from the voltage source and moving the capacitor's plates farther apart, the following will occur:
b. The capacitor's capacitance will decrease.
e. The magnitude of the charge on each of the capacitor's plates will decrease.
h. The potential difference across the capacitor's plates will decrease.
k. The potential energy stored in the capacitor will decrease.
When the plates of a capacitor are moved farther apart, the distance between the plates increases. Capacitance (C) is inversely proportional to the distance between the plates; therefore, increasing the distance decreases the capacitance.
As the distance between the plates increases, the electric field strength decreases. This leads to a decrease in charge (Q) on each plate because the charge is directly proportional to the electric field strength. Hence, the magnitude of the charge on each plate decreases.
Since the charge on each plate decreases and the capacitance decreases, the potential difference (V) across the capacitor's plates also decreases. This relationship is described by the formula V = Q/C, where Q is the charge and C is the capacitance.
The decrease in potential difference and the decrease in charge lead to a decrease in the amount of potential energy stored in the capacitor. The energy stored in a capacitor is given by the formula U = (1/2)CV^2, where U is the potential energy, C is the capacitance, and V is the potential difference.