23.1- CAPACITANCE Flashcards
What is a capacitor designed to do?
store charge
What is used to form a capacitor?
two parallel metal plates placed near each other
When the plates of a capacitor is connected to a battery, what happens?
electrons move through the battery + are forced from its negative terminal of battery onto one of the plates
When the plates of a capacitor is connected to a battery and electrons move through the battery + are forced from its negative terminal of battery onto one of the plates, what does an equal number of electrons do?
leave other plate to return to battery via its positive terminal
As an equal number of electrons forced from the negative terminal of battery to one of the plates and equal number leave the other plate to return to battery via its positive terminal, what does this mean?
each plate gains equal + opposite charge
What does a capacitor consist of?
two conductors insulates from each other
What can be used to charge a capacitor at constant current?
using variable resistor, switch, microammeter, + cell in series with capacitor
When the switch is closed, what is done to the variable resistor? (charging a capacitor at constant current)
variable resistor continually adjusted to keep microammeter reading constant
What can be measured by using a high-resistance voltmeter connected in parallel with the capacitor? (charging a capacitor at constant current)
measure capacitor pd
What can be done to investigate how the capacitor pd changes with time for a constant current?
use variable resistor to keep current constant, and either:
use stopwatch + measure voltmeter reading at measured times, or
use data logger
What is the capacitance of a capacitor defined as?
charge stored per unit pd
What is the unit of capacitance?
farad (F)
What is the equation for capactiance C?
C = Q / V
What is the charge stored in a capacitor proportional to?
pd
