electricity Flashcards
1
Q
electric current?
S.I unit?
A
- rate at which electric charges flow
- Ampere (A)
2
Q
how to measure electric current
A
- ammeter (series)
- positive terminal of ammeter connected to positive of source of energy
3
Q
conventional flow
A
flow of positive charges from positive to negative terminal
4
Q
electron flow
A
- movement of electron in conducting wires
- negative to positive terminal
5
Q
potential difference
A
- the amount of energy needed to drive an electric charge across two points
6
Q
S.I unit for potential diff
A
volt
1 V = 1 joule of energy needed
7
Q
voltmeter
A
- measure potential diff
- parallel
- positive to positive
- opposite bulb
8
Q
resistance
A
- opposition flow of electric current
- fixed / variable resistors
- Ohm (SI unit)
9
Q
resistance formula
A
P. d (v) / current (A)
10
Q
factors affecting resistance
A
length - longer the wire, the greater the resistance
thickness - the thinner the wire, the greater the resistance
11
Q
fix resistor vs variable resistor
A
FIX - resistance value is fix
- cant vary amt of current
VARIABLE - resistance value varies
- vary amt of current
12
Q
resistors in series
A
- if ammeter reading decrease, bulb becomes less bright
- decrease in current means resistance INCREASE
- thus, adding a resistor in series INCREASE overall resistance
13
Q
resistor in parallel
A
- ammeter reading increases
- bulb becomes brighter
- overall resistace decrease
14
Q
variable resistor
A
- rheostat
- slider to left - resistance decrease
- slider to right - resistance increase
15
Q
resistance + heat
A
- the greater the resistance, the greater the amt of heat produced
