5. Electricity Flashcards
1
Q
What is electric current?
A
The rate of flow of charge.
2
Q
What is the potential difference?
A
The work done per unit charge.
3
Q
What is Ohm’s Law?
A
Why current is proportional to voltage under constant physical conditions.
4
Q
How are ammeters and voltmeters considered?
A
To be ideal, with zero and infinite resistance respectively.
5
Q
What is the current voltage characteristic of a semiconductor diode?
A
A very steep gradient after a threshold voltage.
6
Q
What is the current voltage characteristic of a filament lamp?
A
Shallow gradient to steep gradient.
7
Q
How do you add resistors in series and parallel?
A
In series: Rt =R1 + R2 + R3 + R4 + …
In parallel: 1/Rt = 1/R1 + 1/R2 + 1/R3 + 1/R4 + …
