Topic 7 - Capacitance Flashcards
If a particular conductor is earthed, what does the potential difference value equal?
0 volts.
What is the symbol for an earthed conductor?
Diagram in page 3.
What does a smaller capacitor mean for the rate of discharge and charge for the capacitor?
Smaller capacitor holds smaller capacitance.
Faster rate of discharge + faster rate of charge.
If we are using the equation V=IR for a resistor, how do we calculate the Voltage or p.d. across the resistor (Vr)?
Vr = EMF - Vc.
Vc = voltage across capacitor.
When it says initial charge lost, or initial quantity lost, how do you calculate or obtain the fraction remaining?
(Present in Capacitor charging and discharging questions).
100% - the percentage lost.
Check task 10 in capacitance.
If we have a constant current, what equations do we NOT use?
Do NOT use any of the exponential equations for charging and discharging capacitors.
What remains fixed or constant, if the capacitor is disconnected or left isolated?
charge, Q.
In a circuit in a capacitors question, if we have 2 resistors that are both the same resistance or identical, how would we get time constant, RC?
Do RC, and only consider one resistor with the resistance if both are the same.
If we have a graph of charge against pd, what is the gradient of the graph?
capacitance.
What is the gradient of the graph of pd against charge?
1/capacitance.
What is the relative permittivity also known as?
Dielectric constant.
