Current, PD, and Resistance

Question 1

what is current?

Answer 1

the flow of electrical charge carried by electrons

measured in Ampere (A)

Question 2

what is potential difference?

Answer 2

how much electrical work is done by a cell

measured in Volts (V)

Question 3

what is charge?

Answer 3

the amount of electricity travelling in a circuit

measured in Coulombs (C)

Question 4

what is resistance?

Answer 4

a measurement of how much current flow is reduced

Question 5

what are the rules of resistance?

Answer 5

• the higher the resistance, the more difficult it is for current to flow
• increase in resistance, reduces current
• increase in voltage, increases current

Question 6

how does a thermistor affect resistance?

Answer 6

resistance decreases as temperature increases

Question 7

how does an LDR affect resistance?

Answer 7

resistance decreases as light increases

Question 8

Ohmic conductor graph

Answer 8

at a constant temperature, current is directly proportional to the PD across the resistor

Question 9

Filament lamp graph

Answer 9

as current increases, the resistance increases

the temperature increases as current flows

Question 10

Diode graph

Answer 10

current flows when PD flows forward but there is very high resistance in reverse